I'd recommend you do some researching and reading about exhaust systems here on the forum - there are more options than you might imagine. As far as a quad system goes, you'd be hard pressed to find better quality, performance, and sound than an Autobahn Exotics exhaust. Not only that, the price is very reasonable for what you get and the vendor/customer focus is second to none. Talk to Nick at Autobahn Performance and tell him Jay sent you (and no, I don't get a kick-back). You'll be happy you did. You may want to check out and compare other systems first and you'll understand what I mean.
http://www.autobahnperformance.com/