did some research and now im choosing on which combinations will work well. Im trying to keep a lower exhuast note and not too loud, but have performance at the same time. if i just get the y-pipe and maybe later on high flow cats, do u think the sound will change much. and also if i were to get a y-pipe, and later on a cat back, would that make my exhaust system really loud? i was thinking ichiba y pipe with apex n1 exhaust.