I just got a Big Gun EVO X Exhaust for my 2001 650R. The bike was uncorked by the previous owner who rode at the 3000 ft level. I ride at the 5500 ft level, and was hoping the elevation difference would keep me from having to rejet. The problem I am having, is the loss of bottom and midrange power. Is this a jetting issue or is that the price you pay for a large diameter header? any jetting advice would be greatly appreciated.