Okay, ive searched and didnt find my answers so im gonna post. I have a '90 5spd Na Z but with plugged cats and rotted mufflers. what do yall suggest? i was thinking random technology's hi-flow catalytic converters and probably some apexi N1 mufflers for the most flow. at the same time i have to keep backpressure in mind and the fact that it is there for a reason. what advice can yall give me? thanks a lot