I ran the GTPS02 on my old 05 WRX 2L EJ205
Engine mods were 3"
TBE, PW FMIC, GT Spec Headers, GTPS02, Decapped injectors, Walbro pump, Apexi intake, GFB
BOV...
Made 299.3hp and near on 400nm of torque... I'd imagine you'll go close to that even with the 2.5L and TMIC as mine was only running 18psi?
I'd say that Nic is hesitant to raise your expectations on output, as ever car is different, but I'd be suprised if you made less than 280hp with that level of mods...
For the record, my WRX made 227hp with just the exhaust and tune before as well..