I just ordered my Hd shift kit today so obviously I need a new "want to have" item. I have what i believe is a 49cc engine. I still havent measured the stroke but the bore is 40mm. I am very curious as to how loud these expansion chamber pipes are. I like mine fairly quiet and I'm surprised how quiet it is with the stock muffler. Will the expansion chamber still produce good results with out any other mods like carb, porting cylinder, or compression increases? Would it be a waste of money with out some or all of these other mods?