I don't have WB02....you can still tune within reason.
This may be apples vs. oranges, but the Evo IX had an OTS tune from WORKS and was dyno'd, then a custom e-tune applied, then re-dyno'd (same day) and it was ~50awhp bump. Most of the OTS tunes are "safe" since they are for the mass public, so timing is conservative and so are the AFR's. The little tweaks and bump in boost is sure to give you more ponies compared to a OTS tune.
2007 WRX TR | Stage 2 | PAR Gearset (Built by AndrewTech)