No idea on actual numbers. I've got both the Performance exhaust and intake, and besides the obvious improvement in sound, I feel like it's "opened up" the engine more - made it freer-revving and given it a rawer, slightly rude or brash character. This is of course all subjective - and much of it can be attributed to the exhaust note, which is pretty intoxicating, if you're in to that sort of thing.
FWIW, I wouldn't recommend the intake unless you're also doing the exhaust. The exhaust will sound good no matter what, but I felt I would get the most out of it by pairing it with the intake. The intake by itself? Freer revs, maybe, a slight improvement in engine note - but really not worth the money. I only got it because it was an easy DIY and it looks nice in the engine bay - but mostly because, like I said, I think it complements the exhaust nicely.