[damdog05]

i believe ive read somewhre that you can put a 3" exhaust on an n/a, but you dont want any larger than that or you start hurting your performance. and thinking back on what ive read about most other peopls cars, more people stick with a 2.5" rather than go bigger. but thats just on the n/a. on another note, i only have one cat on my car and it passes emission here in atlanta. i think as long as they look under your car and see a cat youll be fine.