Those are very safe pieces there. I have been running the Cobb AP since I had my car. I was one of the first to actually purchase an AP for the 07. Its a great piece of equipment. With your said mods you are still only int he stage 1 category, but the stage 1 tune is a HUGE improvement over stock. And once you continue to upgrade (if you so chose to) you can use the AP to tune for the mods. IMHO you cant go wrong with the Cobb AP. Just check to see if you have a local tune shop that is comfortable with using it, unless you dont plan to mod your car to heavily.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX