Well, I just got the Cobb AP and went stage 2. Can't say that I noticed a huge power change at low rpm's like everyone talked about. However, when I went WOT I immediately found out what the hype was all about. Feels like a bigger turbo and a couple extra liters in that thing. I only have a couple small concerns. First being that I have the K&N short ram intake and not the stock intake which the AP clearly states: turboback and stock airbox. I still don't see how it makes that much of a difference, the bend before the MAF is very slight and can't be much different than cobbs(which I understand is fine with the stage 2 map). I mean how much of bend are we talkin, that would make it a problem. And of course my other concern is the infamous 02 "glass tranny" complaint. I got 90k on the car so I hope it holds up. Overall, the stage 2 is a must if you own a wrx.