If you dont wanna spend that much but you want the roar and not the ass sound of most import mufflers, i'd go with an Axle-Back Mazdaspeed exhaust off of eBay for $195, and then get your local muffler shop to fo 2.25" cat-back piping. At first all I had was the axle-back, as soon as I got the piping my exhaust system reached its potential and I love it. Its has the roar of a G35s exhaust, but a little bit louder. Interior resonance is very high at high RPMs but I love it. My total spending when I was done was $280!