Listen, if you want a really really nice sounding z400 with performance ratings OFF THE ROOF, put a stilleto street bike slip on on it. My friend did it (had to weld some of the mid pipe of the stock pipe) once he was done after 2 hours of cursing and yelling, he re jetted it, and the thing flies accel to the mid range, the pipe might have added like 1 or 2 mph tops on the top end, but DAMN does that thing whale in accel.. Sorry if i wasted a thread i just thought maybe it would be cool to tell people about it. Hey ill get what street bike slip on works



P.s.
The slip on looks sick 2. And it sounds like a beast

 

sounds cool, get some pictures!