I'm gonna take the cat off my 240sx and put a 3" pipe in it's place... also, i'm getting an spexi gt spec exhaust with 3.74" piping... will they bolt up right? cuz they different sizes... anyone have an apexi gt spec? how do they sound?

 

flanges should be the same.

if you're NA that is going to be to much pipe for anything but top end power. 60-65mm would be plenty. 90mm is overkill.

 

^^What he said. If its N/A then that sized piping is ganna be overkill. But if your turboed, great Expect a very low rumble, and its ganna be loud