When the original wrx's came out they had about 230hp and the sti had 260ish
As they went through the V 1-6 this changed and by the time we get to the version 4,5 and 6 the stock wrx was in reality putting out around 165kw atw or around 200kw at the fly. Then when version 7 came in the wrx started to be officially exported to the USA this meant that the wrx and STI had to be properly seperated, So the wrx was chopped back to around 140kw atw and the sti put down around 165kw. (Yes non RA versions 7's were that bad) However with the dawn of the version 8 this crept up again and the wrxs got back to around 150kw and the sti's around 180kw.
If you buy a version 4-6 wrx you can expect a good 250-270hp at the fly. Or around 180-200kw