2003 Subaru Legacy Spark Plugs

NGK G-Power Platinum spark plugs are the best single platinum spark plugs at an economical price. G-Power plugs feature a fine wire platinum center electrode and a trapezoidal cut ground electrode that offers increased durability, improved fuel efficiency

Product Features:

• SINGLE PLATINUM TIP: Fine wire 0.6 millimeter platinum tip center electrode ensures improved durability and a consistently stable spark
• PLATINUM ALLOY: G-Power platinum provides exceptional value with increased performance and longer service intervals than factory nickel plugs
• TRAPEZOIDAL CUT GROUND ELECTRODE: Reduces quenching design produces improved ignitability and performance
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
• RECOMMENDED USAGE: Lower cost alternative to double precious metal spark plugs or as an upgrade to OE nickel alloy spark plugs

NGK Iridium IX spark plugs are specifically designed for the performance enthusiast. Iridium IX provides outstanding acceleration, high fuel efficiency and durability. NGK Iridium IX plugs offer extreme ignitability and exceptional anti-fouling. Tapered c

Product Features:

• SINGLE IRIDIUM TIP: Fine wire 0.6 millimeter iridium tip center electrode ensures high durability and a consistently stable spark
• IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
• TAPERED CUT GROUND ELECTRODE: Reduced quenching design produces outstanding ignitability, improved acceleration, fuel efficiency and durability
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
• RECOMMENDED USAGE: Modified or high performance applications, or as an upgrade to OE nickel alloy spark plugs

NGK V-Power spark plugs offer reliable performance and improved ignitability over standard nickel plugs. Engineered specifically for OE applications, the special V-cut nickel alloy center electrode and concave ground electrode of NGK’s V-Power spark plug

Product Features:

• ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode with V-groove provides consistent performance
• RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
• NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
• TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal

NGK Standard spark plugs (in the iconic NGK ‘yellow box’ packaging) are a proven OE cornerstone and technology customers have relied on for decades. Engineered specifically for OE applications, NGK Standard spark plugs provide OE quality nickel alloy reliable performance and design. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance, while triple gasket sealing prevents combustion gas leakage. Solid 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.

Product Features:

• ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode provides consistent performance
• RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
• NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
• TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal

Increased performance with World’s smallest Iridium Center Eletrode (0.4mm).

Product Features:

• World’s smallest Iridium Center Electrode (0.4mm) for improved spark for maximum combustion
• Patented 360-degree laser welding assembly process
• U-groove and taper cut ground electrode to maximize flame propagation.
• Withstands temperatures greater than 4000° Fahrenheit
• Burnished nickel plating for high temperature endurance and superior corrosion resistance
• Wide range of part numbers for thousands of applications, including classic and collector cars
• Iridium Power

The ground electrode is cut-back from the center electrode to provide a gap. The face of the ground electrode is concave to provide a constant gap to the center electrode. This plug is designed use in all aftermarket cylinder heads used in different types of racing venues including oval and road racing.

Product Features:

• Opens spark face for better ignitability of flame kernel
• Retains less heat, transfers heat to shell faster – reduces risk of pre-ignition
• Dyno testing has shown proven power gains
• Cut-back ground electrode evolved from practice of grinding back the side electrode

Champion® Double Platinum Power™ spark plugs deliver more powerful performance. Featuring exclusive Heat-Active™ alloy, platinum fine wire center electrode and platinum pad ground electrode provide maximum life and sharper spark focus.

Product Features:

• Double Platinum Power – Premium Spark Plug. More Powerful Performance.
• Platinum center and ground electrode for greater wear resistance
• Maintains stable operating temperature under all engine loads
• Fine-wire center electrode for greater ignitability
• V-trimmed ground electrode promotes sharper spark focus
• Heat-Active™ alloy allows electrodes to reach optimal temperature

Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:

• OE grade platinum on both center and ground electrods
• Premium shell construction with machine-rolled threads
• Superior thermal conductivity
• Sustained spark performance over 60,000 miles
• Reduced secondary required voltage, increased ignition efficiency
• Satisfied customers, reduced shop comebacks
• Double Platinum

NGK Laser Iridium spark plugs offer the best combination of performance and longevity. Engineered specifically for OE applications, Laser Iridium spark plugs are tested to the highest standards to ensure quality and durability. Iridium tipped center electrode provides durability six times harder than platinum. NGKs high grade pure alumina ceramic and 98 percent pure copper core prevents the spark plug from overheating while providing reliable starts. Most Laser Iridium spark plugs feature a platinum pad on the ground electrode for even wear in distributorless ignition systems.

Product Features:

• ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction fine wire iridium alloy center electrode provides consistent performance
• IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
• PLATINUM TIP GROUND ELECTRODE: Unless OE specified, platinum protection at the ground electrode provides excellent ignitability and service life
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
• RECOMMENDED USAGE: Best for vehicles with OE fine wire iridium alloy plugs

U-Groove design provides better ignitability for increased engine efficiency.

Product Features:

• Patented U-groove ground electrode design fires leaner mixtures than conventional plugs
• Precision machine-rolled threads reduce seizing and cross-threading in delicate aluminum heads
• Wide range of part numbers for thousands of applications, including classic and collector cars
• Lasts twice as long as most conventional plugs
• 100% pre-fired to assure reliable operation
• U-Groove Conventional

Durability of an OE style plug combined with Power & Torque of high performance.

Product Features:

• 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
• 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
• DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
• DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
• Durability of an OE style plug combined with Power & Torque of high performance.
• Withstands temperatures greater than 4000¦ Fahrenheit
• Iridium TT

Our best spark plug! Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, the Autolite Iridium XP spark plugs feature an iridium-enhanced 0.6mm finewire design and patented platinum sidewire technology to provide better overall durability and a more focused ignition for enhanced ignitability and performance. Features double Iridium-enhanced alloy technology center electrode for improved durability and wear resistance.

Product Features:

• 0.6 mm finewire design improves ignitability
• Patented V-trimmed platinum sidewire technology resists wear
• OE equivalent design is engineered for every engine
• Designed for better overall durability with virtually no gap erosion

Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Platinum spark plugs provide a center wire platinum firing tip which provides reduced gap erosion, fewer misfires, better performance and increased durability. Consider upgrading to Autolite Double Platinum or Iridium XP spark plugs for increased performance.

Product Features:

• High nickel alloy side electrode maintains precise gap
• Full platinum tip assures virtually no gap erosion for long life
• Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)

Autolite Copper spark plugs deliver quick starts, good fuel economy and smooth acceleration.

Product Features:

• Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leak proof)
• Multi-rib insulator reduces danger of “flash-over”
• One-piece terminal post adds strength
• Resistor reduces radio frequency interference (RFI) and electrode erosion

Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Double Platinum spark plugs feature platinum-to-platinum firing which virtually eliminates gap erosion, reduces misfires and increases durability of the plug. Consider upgrading to Autolite Iridium XP spark plugs for increased performance.

Product Features:

• Works to optimize engine performance for a longer life and improved fuel economy
• OE design
• Full-platinum tips; platinum on both the center and side electrodes to promote reduced gap wear
• Platinum ball welding process provides a consistent point of contact for enhanced adhesion

The Spark Plugs are the product of years of fundamental research in the combustion field. The unique patented electrode configuration of these new The spark plugs increases the amount of combustion pressure created during each power stroke of an engine, which results in a marked increase in power output, fuel economy, and reduced emissions in all gasoline engines. E3.56 is a 14mm, 0.750 reach plug with a gasket seat. It fits a wide variety of late model applications, especially import. The automotive plugs have three legs securing the Diamond FIRE electrode to the shell. This allows for excellent heat transfer, and helps to create more turbulence in the cylinder. The patented Diamond FIRE side wire is proven to increase power, reduce fuel consumption and improve hydrocarbon emissions in long-term use.

Product Features:

• E3’s Diamond Fire edge to edge ground electrode provides maximum performance with increased efficiency and a faster more complete burn
• Smoother Acceleration & Idle – The faster flame initiated by the The spark plug results in a more complete burn of the ingested fuel charge. More pressure is created against the piston more fuel is put to work
• Energy – Power output improved up to 6% on average in the typical operating ranges. Results will vary.
• Efficiency – The “diamond shaped” side wire electrode projects the combustion spark in a way that more quickly ignites the air/fuel mixture, thereby creating a significantly faster and larger flame kernel. The result is that more fuel is put to work durin
• E3’s patented Diamond Fire Technology provides a cleaner burning combustion, which translates into fuel savings and reduced engine carbon deposits
• The Spark Plugs are pre-gapped at the factory and cannot be adjusted.

ACDelco Gold (Professional) RAPIDFIRE Spark Plugs are a high quality alternative to Original Equipment (OE) parts. These RAPIDFIRE Single Platinum Performance Spark Plugs are designed for everyday use and are a high quality replacement for many vehicles on the road today. These premium aftermarket spark plugs have high-quality suppressors that help prevent misfiring, an improved plug to boot seal, and a pure copper core for greater durability. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.

Product Features:

• Solid state suppressor, with two-piece glass and brass seal, can help reduce radio frequency interference, regulates spark energy for long electrode life, and helps protect against high combustion pressures
• Pure copper core provides great heat transfer and helps maximize plug durability
• Platinum on center electrode enables superior spark characteristics and can reduce voltage requirements of the ignition system
• Ribless insulator helps optimize plug to boot sea
• Some ACDelco Gold parts may have formerly appeared as ACDelco Professional
• Premium aftermarket replacement part
• Manufactured to meet specifications for fit, form, and function for General Motors vehicles as well as most makes and models

ACDelco Professional Double Platinum Spark Plugs are premium aftermarket plugs, and are a high quality replacement for many vehicles on the road today. With a copper core and double platinum pads on the center electrode, these plugs are designed to deliver long-lasting performance. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function.

Product Features:

• One-piece, fired-in suppressor seal blends three glass types for a gas-tight seal that helps reduce radio frequency and engine interference, regulate spark plug energy, and protect against compression pressures for long life
• Double platinum point pad on center and ground electrode offer excellent durability and consistent voltage demands to help reduce wear on ignition system
• Pure copper core results in cooler electrode temperature for maximized durability and fouling resistance
• Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional
• ACDelco GM Original Equipment parts are designed, engineered and tested to rigorous standards, and are backed by General Motors
• GM Engineers design and validate OE parts specifically for your Chevrolet, Buick, GMC, or Cadillac vehicle
• GM regularly updates production and service part designs to integrate new materials and technologies

Twin-Tip design enables faster flame propagation for more complete combustion.

NGK Laser Platinum spark plugs provide high ignitability and longer service life compared to conventional nickel spark plugs. Laser Platinum plugs are tested to the highest standards to ensure quality and durability. Engineered specifically for OE applica

Product Features:

• ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction fine wire platinum alloy center electrode provides consistent performance
• PLATINUM ALLOY CENTER ELECTRODE: Longer wearing and higher temperature resistance compared to traditional nickel spark plugs
• PLATINUM TIP GROUND ELECTRODE: Unless OE specified, platinum protection at the ground electrode provides excellent ignitability and service life
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
• RECOMMENDED USAGE: Best for vehicles with OE fine wire platinum alloy plugs

Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:

• Copper Plus – Dependable Performance.
• Copper core center electrode allows for accurate control of heat range for longer life
• Patented TinTac and ULTRASEAL coated shell for maximum corrosion resistance
• Patented SAC-9 semiconductor resistor for maximum EMI & RFI suppression
• Built to ISO and SAE standards for proven performance

ACDelco GM Original Equipment Conventional Spark Plugs are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These Conventional Spark Plugs are designed for reliability and efficient performance, and are a high quality replacement for many vehicles on the road today. Their high-quality copper cores and outstanding suppression characteristics deliver reliable performance. They are also available for Marine applications. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco GM Original Equipment parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.

Product Features:

• GM regularly updates production and service part designs to integrate new materials and technologies

Autolite Iridium Ultra is an engineered OE replacement iridium spark plug. A laser-welded 0.5 mm iridium finewire center electrode provides optimal fuel efficiency, acceleration and focused ignitability.

Product Features:

• Autolite Iridium Ultra is an engineered OE replacement iridium spark plug.
• A laser-welded 0.5mm proprietary iridium alloy finewire center electrode provides optimal fuel efficiency, acceleration and focused ignitability.
• Nickel-plated shell to resist corrosion.
• High-alumina ceramic insulator for increased strength.
• Laser welded 0.5mm Iridium finewire center electrode.
• Proprietary platinum sidewire technology.

NGK Ruthenium HX High Ignitability spark plugs are the best in class plug for todays modern vehicles. Patented Ruthenium technology offers the most advance tip technology and delivers the highest performance and life expectancy. Created from advanced OE technology as a high ignitability plug; Ruthenium HX spark plugs come with patented, specialized OEM DFE and PSPE tip designs. NGK Ruthenium HX High Ignitability spark plugs provide a more complete fuel burn resulting in a quicker throttle response, smoother idle and better cold starts. Ruthenium center electrode provides industry leading durability.

Product Features:

• HIGH IGNITABILITY PROJECTED SQUARE PLATINUM ELECTRODE DESIGN: Combines 0.6 millimeter ruthenium center with a unique cut-back PSPE ground electrode
• RUTHENIUM ALLOY CENTER ELECTRODE: NGK’s patented ruthenium technology produces maximum performance, ignitability & durability at high temperatures
• PSPE DESIGN: Projected square platinum electrode shape of the ground electrode provides the best ignitability and service life for high heat engines
• SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
• TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
• RECOMMENDED USAGE: Modern vehicles using OE PSPE type spark plugs or for those seeking an aftermarket plug with the latest OE technology

Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:

• Latest OE technology with DENSO’s patented Iridium Alloy (90% Ir) and fine wire center electrode
• Platinum ground electrode for extended life
• DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
• Sustained spark performance over 100,000 miles
• Lasts up to three times as long as conventional plugs
• Endures extreme temperatures greater than 4,000 degrees F associated with high-performance ignition and special fuel systems
• Iridium Long Life

Champion® Platinum Power¿ spark plugs deliver powerful performance. Made from exclusive Heat-Active¿ alloy, a fine-wire center electrode and V-trimmed ground electrode provides sharp spark focus.

Product Features:

• Platinum Power- Premium Spark Plug. Powerful Performance.
• Platinum center electrode for long life
• Fine-wire center electrode for greater ignitability
• V-trimmed ground electrode promotes sharper spark focus
• Heat-Active┐ alloy allows electrodes to reach optimal temperature
• Platinum tipped center wire resists wear and helps to maintain proper gap spec over life of the plug

4X longer service life compared to standard copper plugs Bosch OE Finewire Iridium is engineered to deliver both High performance and long life. The Bosch Iridium Plug provides original equipment design, materials and processes represent the best of OE technology. The ultra fine wire design and laser welded tapered ground electrode deliver optimum performance, while the iridium center electrode and platinum ground electrode help it to go the distance. Center Electrode Core Material: Nickel-Yttrium and Copper and Iridium – Center Electrode Tip Material: Iridium – Ground Electrode Tip Material: Nickel-Yttrium and Iridium

Product Features:

• OE design for optimum fit and function
• Center electrode is an ultra fine wire design.
• Provides broader heat range to resist pre-ignition and fouling
• Delivers exceptional ignitability and performance
• Tapered shape ground electrode
• Laser welded iridium-platinum alloy inlay
• Nickel-plated shell with rolled threads
• Anti-seize and corrosion protection

Champion® Iridium – the ultimate element. This spark plug’s fine-wire iridium center and platinum ground electrodes provide the sharpest spark focus for maximum performance.

Product Features:

• Champion Iridium – Maximum Performance. Premium Spark Plug
• Iridium center electrode delivers maximum life
• Fine-wire center electrode and V-trimmed for greater ignitability
• V-trimmed ground electrode promotes sharper spark focus
• Maintains stable operating temperature under all engine loads
• Heat-Active┐ alloy allows electrodes to reach optimal temperature quickly