I planned on going today to build me a new single exit catback exhaust.

My original plan was 2.5 into a magnaflow muffler to a 3inch tip.
My friend suggest I go just 2.5 piping straight back
Another suggest I go 3inch straight back - I searched and saw you should go 3inch if you plan on doing a turbo in future

What are the main pros/cons of each. I live in virginia beach and it seems cops have nothing better to do then ticket cars here. I want it to have a nice roar im not to worried as long as it doesn't sound like when you know how loud it gets when you go through tunnels haha.

 

pro: put a muffler on it and stay at 2.5 if you don't want to worry about cops.
con: no muffler 2.5 or 3 worry about cops

 

If your exhaust looks large, the cops will give you a second look.
If they think its ridiculously loud on the second look they will pull you over.

I like the large pipes with resonators/ good mufflers, cause as soon as they see its not loud they move on.

 

So are you suggesting 3in piping with muffler? to slient it a little?

 

Its really up to you, but keep a muffler on it either way. straight back makes it loud and while our engines generally sound good, it probably wont be sounding as great as it could be.

I just noticed your profile says sc400. i thought we were talking about 2j's here.
haven't seen to many single exit sc400's. If thats the case I wouldn't consider 3" too large for 8 cylinders to breathe, and I would just run that with a good muffler on the end.

when its done give it a few weeks to break in and if it sounds a bit raspy go back and have them weld a resonator on the straight section.

 

I removed the giant mufflers on my gs400 and love it. I just straight piped it after the joint resonator.