You are going to struggle to hit that sort of power with a 25 turbo or 2510, even the 2530 IMO.
There is no real need to spend all that money on head work and balancing if, more so if your on a budget.
Grab your stock 20, strap a TD-06 to the side, cams, 550's, Z32 (other supporting mods) and decent tune and you will have near your target power.
If it goes pop then you can buy another motor for $500 and swap everything over or go with the Tomei motor or rebuild
You mentioned doing this on a budget and not being able to afford a 2530 but your talking about forged pistons, rods, head work etc which is going to cost you a mint