Roush 403936 Exhaust Kit for Mustang GT/GT500 Increases horsepower and torque, Increases fuel efficiency No welding or cutting required, Fits 2005 - 2009 Mustang GTs and Shelby GT500s with the stock rear fascia Generates deep off-road exhaust tone Comes with OEM clamps that won't damage pipes when tightened and provide a leak-proof seal Manufactured using CNC bending to create smooth mandrel bends (resulting in higher flow), Made from 2.5-inch diameter stainless steel tubing