this is a good pipe for my wr250r only reason i have it over yoshimora rs4 is the yoshi is a bit loud and the noise wears me out i cant wear ear plugs so it gets to me on long rides preformance wise yoshimora rs4 is about 40% better pep and has a nice sound think yoshimora is a better run company also as fmf likes to blow smoke and not make stuff when they say that said fmf does make a nice pipe works well good sound and more pep than stock q4 is good for my ears i used the mega bomb for both slip ons it works well and gives more pep