I have the FMF Power Bomb header with PC4 exhaust on a 2001 YZ250 F and would like to decrease noise level. 2 Questions. Does anyone know how I could decrease the noise on the PC4? Quiet Core insert shows on the FMF web site but looks like is only for 2002 model. Mine is a 2001 model and is a one piece unit. Second, if I use the stock exhaust with the PB header, will I only loose top end power?? Any thoughts/help are apprecited.