how much hp do you have? i know a catback will not affect your performance if you are under 350WHP.
i dont know know for sure. Its estimated probably 350-400...dont know for sure its just what i was told
98 GTP - VS Competition Cam, ported and polished M90 eaton w/ 3.1 pulley, ported TB, TOG headers and ported manifold, 2.5" RAT catback w/ Magnaflow mufflers and Magnaflow high flow cat, custom tuned PCM from ZZPerformance
05 GTO - Stock for now