First off the Cobb stage one map does not give you that much power at all. I have the stage one map from a V2 on my 07. It gave more power Im sure, but dont have the dyno to prove it. It basically makes more boost, and sooner, and smoothed out the power band. You also have to remeber/realize that every car reacts to mods differently, thats just the way that is. The AP might give you around 33HP if you put a downpipe on with it, I personally dont know becuase I havent got that far yet with my car. As far as the Borla or any CBE (cat back exhaust) goes there is next to no gain in power wise, its all looks and sound. The main restriction on the Subaru exhaust is the DP where it connects to the turbo. Its a small tube with a flat flange that covers alot of the turbo restricting the flow.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX