I have the AP and the SRI from COBB and I would recomend that you run the stage 1 map if you get it. I went from 15 to 17 psi with it, no hesitations or chugging. The power delivery is smooth and holds power until about 6,400 RPMS. Deffinatly worth it. First though I would really recommend getting some kind of aftermarket bypass valve to ensure you are holding the full 15 PSI without a tune. I was only running 13.5 or so without my bypass valve. Other than that, runs great and I recommend it. As for stage 2 it is only suggested to be used with a full turboback exhaust. Hope this helps!