Okay heres the car.

Stock as hell, I know... Nice how the flash blurred out my
tag # ive got another muffler im going to put on
and thinking about doing a 2" exhaust and do away with the resonator..
is there a thread with underside photos of exhausts?
and i was wondering what you guys think as far as
pipe size,catalytic converters,& resonators..

 

I'd recommend any where from 2.25" to 2.5" for piping if you are N/A.

 

2.25 is the best way to go just get a carsound cat and an 18in resonator and well it all depends if you want it quiet or loud but me personally i'm running 2.5in piping no cat 22in resonator and a 2007 Si muffler and it's really nice purr to it...

 

I've got a 4" burned tip muffler im sticking on my car
and i was thinking about doing away with catalytic converter
and resonator i kind of want straight piping but clearance will be an issue.
after the exhaust i'm going to slam it.

 

I would keep the cat and resonator for a DD, unless you love the feeling of your ears ringing. I have a 2.5" piping with a megan test pipe from my headers and it's pretty nice... a bit farty though.

Just make sure to hold onto your warranty card for parts you get. The magnaflow cat I had broke on me in the welding and soon after clogged up cause major problems and had no warranty papers.