The Edelbrock Stage II Upgrade Kit (part #15882) allows customers using the 1588/15880 supercharger (2011-14 5.0L Mustang) to upgrade to Stage 2. The kit includes a 3.25 in. supercharger pulley, a complete competition air intake system, a 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 must be signed and submitted by the customer and accepted by Edelbrock to receive the race-only calibration file, which will need to be modified by the customer for the specific race engine configuration.