The Edelbrock Stage II Upgrade kit part # 15866 allows customers using the 1586/15865 supercharger (2015-2017 5.0L Mustang) to upgrade to stage 2. The Edelbrock Stage II Upgrade kit #15866 includes a complete, competition air intake system, 90mm Throttle body with adapter, fuel pump upgrade 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.