What is the quietest exhaust to put on this bike? I am riding my XR400 which is very nice and peaceful compared to the 426. We also won't be able to ride my brothers 426 on out property until we get it settled down with the sound because of the neighbors. Any suggestions? Sacraficing some power isn't an issue cuz my brother hasn't ridden in 2 years and Im pretty sure the bike will still be plenty fast for him.