You wont see 250whp with those mods it is going to take a lot more than that.
I'd start off with a gsr swap since you are going to be building the shit out of it and its cheaper. Start with:
balanced and blueprinted block.
make it 2.0
aebs sleeves
some aftermarket rods, ie crower
itr crank
some good pistons like je 84.5mm to bump the comp.
port and polish
some serious cams, toda, jun, etc
larger injectors
upgrade the fuel system; rail, pump
head gasket
larger throttle body
a good header; hytech, ericks racing
upgrade ignition; wires, coil
upgrade the tranny
and also some serious tuning. I'd go with hondata and a chipped ecu like a p28. It will not be cheap at all. I bet all that stuff will get you around 220-230whp. You may also want to look into itbs, they are nice.