BuGS

It sounds nasty!!! I would stick with 2.5 or less

89ef8

pointless 2.5 is the best i think

anela44

I think that 2.5 should be better. I have a 2.5 in my coupe. 3 in a turbo car.

AaronZ34

Get a better engine. All of the sudden, 3" > 2.5".

anela44

3" in a n/a car will also be hella loud...................

turboknightmare

do a 2.5" setup, dyno it. then do a 3" setup, dyno it

post results.

MoFasterthenUr's

2.5" is more then enough. if you put 3" you'll lose low end hp, and you'll feel the power loss.
I had a 4-1 header, 2.5" and glass pack on my NA LS, and I could feel the loss in power at low end. it started to pull hard at 4500 rpm.it would have been much better if I had the ls with cams and other bolt on's with the 2.5". but in GSR's 2.5" is good.
Even with small turbo builds 2.5" is good enough. when you start moving up more then 250hp, that's when I'd put 3".

You got to remember back pressure. if you don't got enough back pressure you'll loss hp.

camsshaft

^ I agree. You really don't have a need for anything more than 2.5"

40 psi 4g63

Depends on where you live at and the laws varies on what you can have or get away with.

It will probably only hurt hp or torque a little

turbominime4door

trade me your 3in for my 2.25 and then we both win