Use this exhaust system when you want to upgrade your 2005 - 2009 Ford Mustang for a more powerful driving experience. It's perfect for Mustang enthusiasts who love a sporty look and aggressive sound. The main piping is 3 inches in diameter, and the tips are 4 inches polished double - wall angle cut. It replaces the exhaust system from near the catalytic converter on back and is easy to install thanks to its direct - fit design.