I wouldnt really waste your time with an expensive CAI (I know you didnt mean intake manifold.

).
The gains are minimal at best.
If you really want one I would get the K&N CAI. It seems to have the least bends.
Im sure the SLP exhaust system is nice, but for the $$ you could probably get a identical performing exhaust system for less.
Magnaflow has a nice stainless steel system (magnaflows or mangnapacks) depends on how loud you want it.
I still say get a rear end gears and a nice set of D/R's.