hey there,
my mates r33gts-t has a 4 inch exhaust so i was just wondering what size would be best for a n/a cat back 2.5 or 3 inch?when i get the cash together for a 32 or 33 this will be the first thing i do.i noticed most are 3 inch or more,also would a 2.5 inch give the mad skyline note and much of a power gain.
And would a 3in cat back be to noisey?