It's the intake. I had AEM CAI also in my car before. To tell you the truth, I think my car ran slower with it in, then with the stock air box. It ran even slower with the Bypass put in (yeah, it rains in California). Anyway, I put my stock air box back in, and love it. It's not nearly as loud (always a plus). I think at first, with the AEM CAI, you feel faster because you "sound" faster. I don't know if that makes sense to any of you. Good luck with whatever you do though.