I don't know if this will help but I ride a 310 done by Foward Motion, mobetter and pump gas. I have used a PC pipe,FMF gnarly, and stock pipe. For top end power I get the most power with the stock pipe, for bottom end the FMF, the PC is ok everywhere. With the 99 ignition and the stock pipe it screems on top.I trail ride so it has the FMF pipe and a 98 ignition on it and a 13oz flywheelweight right now. On mine it seems to me the lower volume pipe makes more top end. Good luck. Ed