The Edelbrock Stage II Upgrade Kit part No. 15882 allows customers using the 1588/15880 supercharger (2011-14 5.0L Mustang) to upgrade to stage 2. The Edelbrock Stage II Upgrade Kit part No. 15882 includes a 3.25in. supercharger pulley, complete competition air intake system, Gatorback belt, and an updated calibration file. This upgrade is intended for racing applications only and is not legal for use on pollution-controlled vehicles. A properly completed race-only form will need to be signed and submitted by the customer and accepted by Edelbrock to receive the race-only calibration file. A race-only calibration file will need to be modified by the customer for the specific race engine configuration.