Ok so backpressure is not always the answer, and is not always the bad guy either...I will agree 100% it depends on the specific motor at hand...
http://www.bigcitythunder.com/pages/und ... xhaust.pdf
My stock gsxr 600 can not adjust its own air/fuel mixture, so i chose to run a supertrap, the power band seems lower than stock with the increased back pressure, i can adjust the disks to compensate...
http://www.bigcitythunder.com/pages/und ... xhaust.pdf