my car:

CF hood, CF hatc, AW header, ZPI s-pipe, K&N CAI (obtained them in that order)

with the K&N cai the car was preppy and it drove great. little low end gain but a sudden TQ gain (my head pulled back) at 3.6rpm to redline.
havent had the chance to dyno

now
as you all know, the injen intake piping is LITTLE bigger than the K&N piping but i thought thte filter might contribute to a lot of HP gain.
so i put the INJEN filter on the K&N CAI.

review on that:
the injen puts more LOW end power and TQ.
everything is smoother, i feel my head push back smoothly instead of suddenly
car seems to pick up faster.


disclaimer: NO DYNO's ARE GIVEN, this is based on personal experience

thought i shoud share :D