I am looking 2 replace my stock piping on my evo, I have an AMS fmic. As far as piping goes, what would b the best and most affordable to get. I have been looking at many brands and mostly all of the claim to increase hp in between 8-15hp, all varying in the price. Is AMS, BUSCHER, AND ETS, pretty much selling the brand name. What about Fujita, Injen, weapon-r those seem to be more affordable, do they perfom as well? Tnx a lot for the input..