more airflow is needed. Just looking at a set of precats next to a set of mandrel bend downpipse and you can really see how much better they flow. I would say that with stock turbos the spool up would be better but power gains would only begin to be really apparent in the 17-19psi range as the stock turbos just dont flow enough air below that level to really utilize the flow of downpipes. With big turbos the difference is huge, especially when you get to the 18+psi range.
1990 Twin Turbo 5spd Stillen Stage XI+ "No Show,All GO" 1999 Maxima SE 5spd
ECZA member #0314
..."If it doesnt make it faster, I dont care"...yellowZXTT