Is the monza performance catback a good system for the 2nd gen? Will it work on the non-turbos? How much of a gain in power is to be expected with it combined with a K&N fipk intake kit? These are all the power mods I plan and I just want to know if it's worth the $500. I've learned that neither of these type of mods do much unless you do them both together.

18-22hp is expected from intake and exhaust usually... don't know the exhaust your talking about. maybe put a link so people can look at it and let you know what they think