Pacesetter Cat Back Exhaust System The exhaust flow of an engine has a direct effect on its performance. MONZA Performance Exhaust Systems for the 2nd gen Dodge and Plymouth Neon utilize the right combination of 2-1/2" diameter, 16-gauge, mandrel bent tubing and a lowback-pressure, high- flow performance muffler with a tailpipe exiting on each side of the car (a true dual exhaust) for cooler, smoother operation and increased performance. The MONZA Performance Exhaust System for the Neon is designed to replace the original equipment muffler system and attach to the stock catalytic converter ("cat-back"). Each carries a limited three-year warranty.