I want an aftermarket exhaust that's lighter than stock, and delivers a real performance increase over the uncorked stainless can. I'm curious if anyone has ever tried the GYTR-carbon exhaust. It's supposed to deliver 3.5 hp bottom end, and 1.5 on top. It's the only exhaust that I can even find a spec for horsepower increase. The Yamaha dealer said there's an insert for it if it's too loud. Thanks.