The Roush Performance Axle Back Exhaust is the perfect upgrade for your Mustang. Featuring an open-chambered designed muffler, this Roush Exhaust features an aggressive sound that is unique to Roush without the boom/drone found on many other aftermarket exhaust systems at cruising speeds. Roush Exhausts are made from stainless steel and are finished with a chrome flashing process. The exhaust tips are embossed with the Roush logo. Roush Exhausts are completely bolt on and can be installed with minimal effort. All necessary hardware and instructions are included. A new Roush Rear Valance is also included to accommodate the square tip design of this exhaust. The part number for this item is Roush 421154 and it fits 2011-2012 Ford Mustang (3.7 V6 Models).