I'm with you, Steve. Crazy loud exhaust noise on our lovely CBRs is like that loud Texan who is all hat and no cattle. Tried a mod on my Yoshi by constricting the very inside end of the "low volume insert" pipe by cutting inch long cuts every 1/4 inch and then folding the ends together to narrow the inlet opeing tp about 1" in diameter , and...like with your experience, it got even louder and raspier. So I straightened it all back to near original. Back to square one. If it wasn't for the fact that the funky looking (cast iron heavy) stock pipe is soooo silent, I am almost tempted to refit it.