google magnaflow, go to their site, order it from them. They come w/stickers and a hat and shit, so judging from where you want your car to be, stickers would be a good start as well.

But really, magnaflow isn't too bad. I <3 their catalytic converters made by "carsound" but w/e

I say save your money....
Buy a full catback.

500 bucks is not alot when you consider the return you can get for it. Selling a greddy SP2 will be easy, and you will get alot back versus selling a custom pieced together ebay exhaust. Same goes if the car came with it.

Not to mention the sound from a nambrand catback/turbo back is a good way to brag.