what cat back exausts are avalible for the protege5's? i got an intake and would like to get a new exaust as well, ive heard people talking about mazdaspeed exausts but are they cat back? any noticeable gains? i don't want a fart pipe just a one that will get me more power. BTW the more silent the exaust the better, i actually want the exaust to be quieter than stock but i don't think thats gonna happen