i run them, they sound allot like t5's alittle deeper tone untill you get on top and then they sream like nothin else. they are loud around 105 db with out the spark arrester, with arrester don't know never run it. good mid and top end pipe they pull allot harder than fmf fatties and about the same as t5's. they sound sick, deffinatly turn heads. they are louder than cpi inframes by far.