I have tried several expensive exhaust systems and have ridden both my buddies beefed up YZ426F's and YZ450F's. I have a 99' YZ400F because of the green sticker and I got a super beefed, modded bike hardly ridden, never raced for $3,200 last year. I have the E-Series S bend, White Brothers (with 14 plates installed.) I have no idea what the former owner did to the jets or motor, just that this pipe is night and day over the competition and by far the best sounding pipe on the 4 stroke market. I get huge grins from other people when riding by. It sounds very wicked and sounds like the business end of a 10 gauge shotgun, Ozarks style. I firmly believe in the tunability of plate systems. Once you have a non-plate exhaust, you're stuck with it. If you don't like the sound or the power band change, you just blew $800-$900. With this I can tune for different power band and conditions. I have all 14 plates on it. I tried 8 and 12 and was not happy. I couldn’t believe how much power I lost with those 2 attempts.