I am in the process of modding my car. I dont know how much HP the stock sti block can handle. I am putting in the gt30r .63a/r kit, perrin fmic, injectors, fuel rail. From researching it seems that most leave the block and heads alone. I am anticapating around 375awhp on pump gas and W.I. The only other area to upgrade seems to be the clutch. Stock tranny pretty strong I heard. I appreciate your responses.

 

you'll be fine with the block, with a proper tune it'll last a long time.

Assuming this is an STi? otherwise you're tranny will be on borrowed time.

 

Sounds safe to me.
I'm making that on a td06-20g/fmic/ewg setup.. I'm surprised that 30r's don't make more on pump gas. I know on race/meth injection it'll really shine, but IMO you'd be pushing your luck on the stock block.