This modification includes the pipes, muffler, and sometimes the resonator. The term "cat-back" itself signifies that everything behind the vehicle’s catalytic converter is being upgraded or replaced. Milltek's Sport Catback Exhaust Systems are designed to compensate for the sound reducing qualities from the particulate filter and significantly improve the sound aesthetic of the exhaust system.

Considering cat-back exhausts replace more restrictions, they typically offer increased performance and noise compared to axle-back systems