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 Edelbrock Stage II Upgrade Kit part #15882 includes a 3.25in. supercharger pulley, complete competition air intake system, GT500 fuel pump, injectors w/ adapters, Gatorback belt, and an updated calibration file. This upgrade is intended for racing/off road applications only and is not legal for sale on pollution controlled vehicles. Before a tune can be released complete the disclaimer form and send it back to us in order to receive the appropriate calibration file. This form can also be completed online.