| pretty common knowledge that an n/a motor like a bit of back pressure where as an FI motor like to flow its ass off, to a certain extent. im not saying locust2000 is wrong either with his findings in said book, but do you ever see turbo cars going in for new exhaust systems and coming out with a nice 2.5" exhaust?? in fact if you can find an exhaust specialist that would sell a guy with a turbo car looking for maximum performance a 2.5" exhaust over a 3" i'll sell my 3" exhaust and get me a mint new 2.5" one.
OP: end of the day mate 3" is ideal if your going to be putting out decent amount of power, if your on a budget and already have a 2.5" exhaust system im sure it will be suffice |