I understand where you are coming from.
I bought mine through Perrin which is very good about even tweaking OTS maps if you do have an issue with the way it works (which I will have the option of using either map, Perrin or Cobb). I only have a cat back exhaust, everything else is OEM on the car so it should do alright. A protune/dynotune/customtune would be ideal, however returning those to stock without the use of an AP isnt easy, plus the hassle of locating an AWD dyno around here is a little drive, I think Moon Performance in Lake Placid is the closest to me.
Piston rings like to crack in the GR’s and I have been on the shitty stock OEM tune for 35K+ miles, its even the original tune before the recall that was supposed to address it, so anything has to be better. :lol
What year is your WRX?