Just a thought on this but, from what I have heard our stock exhaust is 2.5". If this is correct then can we keep the stock 2.5 to the cat and then run 3" after the cat and still use the back pressure and get a pretty kick ass sound.

 

Yes the exuaust is 2.5 inches until it reaches the rear axel then goes down to 2.25 inches and connects to the muffler. Just replaced that section with a 2.5 inch pipe and you'll have a full 2.5 inch exhaust. I'm going to be doing this soon actually.

 

3" is way overkill for you

 

the downpipe is not 2.5", after the cat as you say is 2.5" till it goes over the axel and reduces to 2.25", if your not going to plan on doing anything extravagant then just swap the rear muffler for a less restrictive magnaflow or straight threw, since even a fully 2.5" exhaust is still over kill, thats what almost all the 2.0 sc guys run and there pushing anywhere from 50-100 hp more then the stock 2.4 n/a