Edelbrock E-Force Supercharger Pulley for 2005-2009 Mustang Gts.
The E-Force supercharger is impressive enough. However, if you purchased the tuner kit or are just looking to up the power level on the base kit Edelbrock offers several size upgrade pulleys to help achieve the power level you are looking for.
CJ's recommends upgrading the fuel pump if you use the 3.25" or smaller pulley.