Always keep an eye on your DAM/IAM..Anyone who has and AP2 can see it on demand, otherwise you need a tactrix cable and a free program called "learningview.exe".
STIs should be a 1.0 for best and never below a .5
Early 2.0l WRXs should be a 16 and never below an 8
2.5l WRXs are the same as the STIs 1 for best and never below .5
If you ever do find your not at the max you problably have very poor fuel, a tuning issue, boost leaks, manifold leaks, blocked intercooler, and a few more items.
I just got a car dropped off last night that has an IAM/DAM of 0 and its a WRX, bad bad hope the internals are still ok.