Umm.. not really sure I have an answer for you, but I know that God (Of Godspeed Motorsports Inc) had about 311 AWHP (almost 400 crank HP) on his car. I think he also commented that 330WHP was within reach also.... Hope this gives you somewhat of an idea as to what has been achieved so far with this engine...

I do know that there is someone on the "other" forum who makes over 400AWHP on his car, but I believe he is using an STi 2.0L engine.....

 

according to Trey Cobb at cobb tuning, the WRX engine is actually stronger than most people think, with exceptions that the pistons aren't forged, nor is the block reinforced. just by fortifying these components, which may not be very cheap, i would say that the stock block can handle a good amount of power. i would think that the transmission would break way before the stock block would, i can tell you that much.