The Ford Mustang Exhaust Extreme Performance Kit gives your Mustang that rumble sound letting other's know you mean business while increasing the horsepower and torque of your vehicle. The increased power is generated due to the higher flow system as compared to a conventional exhaust system. Though this particular exhaust for the Ford Mustang creates more sound outside your car, it doesn't create the typical off - road exhaust drone inside. The exhaust system is manufactured using a CNC bender to create smooth mandrel bends. This process maintains a consistent inside diameter through the bended area and allows for a significant increase in flow over stockserrated - bent pipes. This Ford Mustang exhaust kit is made from high - quality 2.5 - inch diameter stainless steel tubing and has 4 - inch diameter tips made from polished 304 stainless steel and embossed with the ROUSH logo. Fits 2005 - 2009 Mustang GTs and GT500s with factory rear fascia.