We have a new 96dB rule in Calif., for bikes ridden on public land. As a last resort, I can run a quiet core, at least on the 400EX (PowerCore-4). I am reluctant to mess with the (very loud) Z400 (Ti-4), because the pipe really gives the bike great low end (which it REALLY lacks in stock form).

Anyway, anybody running a quiet core?? How does it effect power?? If it just puts me back to stock performance, I have wasted a lot of money!! Actually, I can see some advantages to having a stealthy machine. There are a lot of dual-sport guys who ride the hills around my house, and nobody has a clue they are even out there. "Less sound, more ground"!!!