With all due respect as well, this is my 2c. I don't know if you have driven a ZRE with a CAI or not, but I just recently removed Injen CAI from my ZRE, I'll just say that it feels less responsive and pull through the revs now without the CAI. About it being a "weak" engine, I agree it's not the most powerful engine but I was quite surprised (and my friends were too) how zippy the manual ZRE can be. For it being a 1.8L 100kW engine, it is not bad. Yeah, I wished it came with LIFT, but it's good enough to beat commonwhores and falcons around the track. :P Note: I have driven ZREs with the CES, Injen CAIs but not with the Blitz. CES CAI - add heaps more torque through the revs Injen CAI - add more torque through the revs but more in mid-high revs Blitz - looks and sounds it goes pretty decent (one of the ZRE members here has it) My 2 cents. Your car, your money. :) I have driven ZREs with CAIs and it does a difference. Up to you if you can justify to spend the $$. :D