[IdealSupra]

when does this pipe actually make a difference, it seems like it is not necesary until you try to run like 15 psi

also, what kind of improvements does it make?

as you are almost correct in the fact that it wont help you noticeably until you start upping the boost....the pipe is a much better design then the stock 3k pipe.... the stocker is a bottleneck design and the hks is the same diameter for the whole thing.

hwoever i agree in the fact that its not worth paying more then 40 bucks or so for it...just to have the HKS on it.