You can just get the AP and run their Stage 1 OTS map and either sell it used or keep it for a pro-tune later on. I just put Cobb's stage 1 OTS map on my 06 STi and it really felt a lot different. Power delivery was a lot smoother, torque peaks sooner, boost peaks sooner and tapers to red line better. And you can log your data, and send it into Cobb if you have any concerns about it.
edit: It is a pretty safe and reliable map, and it comes in a conveniently sized package. Check Nasioc, you can get them new for about 525 from the vendors. and around 400 used.