Thats a blitz (or a knock off of it). I switched my Cobb CBE for that right before I left for a field problem. The difference between your current exhaust and Cobb are night and day. If you get a tune now, then get the AP you probably wont be able to use it. Unless your tuner doesnt lock your ECU. Most due tho so no one can mess with their stuff. If you are going to buy the AP do it either before the DP, or when you get the DP and do DP install and stg2 at the same time.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX