Alright, as of now I have only a AEM CAI and stock headers, stock catalytic, no resonator and 2.25" piping to a flowmaster 60 series. When I start up my car, my exhaust sounds unbelievably annoying with the wonderful tin can sound of so many cars we here. Once the car is warmer, the sound sort of muffles a little but is still there. Is my piping too large for the small amount of airflow coming into it? It almost has a hollow sound. Would a high flow cat (thinking Mugen) help out and push some more air threw my exhaust to get a little more “full” sound? Im trying not to spend the money on new headers so any opinions or suggestiions are helpful. Thanks.
a high flow cat will most likely be louder than your stock cat. It will flow a little better… but usually when you flow better its louder, not quieter. obviously this depends on the exact cat you’re running, they’re all a little different.
adding a resonator will help get rid of that raspy noise. A resonator will mellow out the sound but not restrict flow like a cat will. So, basically your best methods to cut back the noise would be to add a resonator or two (depending on how loud it is) and/or change to a different muffler that is quieter.
Or just buy an RS*R 
Originally posted by 91IntegGS
Or just buy an RS*R
-Jon B