Why would anyone replace the stock exhaust cat-back with an aftermarket system?
A. Primarily for performance reasons. The stock cat-back exhaust is very restrictive, intentially to keep noise down. Aftermarket cat-back systems are usually 2.25 inches in diameter and have only one muffler which is designed for performance using a “straight through” design in the muffler. The pipes are bigger, the bends are smoother, the muffler is a better design. The result is a better performance, but they are also louder! Which is another reason many people replace the stock cat-back with a performance cat-back, for the sound. Q.
