the 300 to 325HP is what I am shooting for also as its at the limit of what return-less fuel system can do. you can do the 300ish HP with a boost a pump and a turbo size that would still make it fun for a DD... However you are also going to need to upgrade the transmission (clutch and will want a limited slip differential). Realize though that a Foci with 300-350Hp is almost 3 times the amount of power out of the same block.
I am right there with you on the money side... have a few hundred every month or so to spend so getting pistons here, rods there, bearings down the road, ect... is still more $$ possible for me than a lump sum.
Many people use the probe pistons or the JE pistons. dont think you will go wrong with either.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)