What would be the gains of one vs. the other? How good is the factory header? It seems HMF and FMF are the only two that make headers, anyone else?
I read your threads about that. But I also read that the FMF muffler will fit on the stock header. Wouldn't they have to be the same size?On most street bikes, the difference between slip-ons and full systems is around 7-9 hp, not including the rediculous claims that some pipe makers say. So on a quad, single cylinder and mostly a straight running pipe, I would say around 3-5 hp gain. These numbers are only based on my experiences with many years of street bike modifying and stuff. The problem I have found is that the FMF header will only work with thier cans, due to collector sizing.