Not much point conjecturing about how much power you need. The question is how much money have you got to spend, then you work out a package from there.

Decide if supercharging is ever going to be option. That will dictate what needs doing to the cylinder head both now & later. For supercharging, you want the best exhaust porting possible, nil shaved from the head & intake porting is optional. That same head would also work very well if fitted to a B20F with stock cam or B20B with mild cam & you'd have the joy of running on the cheapest grade of fuel available until the supercharger was fitted.

Now if you wanted to end up with a 2x 45mm sidedraught Weber car or a MicroSquirt injected car (or even a K-Jet car), then you get X amount of porting done to the intake ports & the compression raised to Y.

X is determined by how much lift the camshaft has.(Which is inversely proportional to how long the cam will last) Y is determined by how much duration the camshaft has, you can't choose a compression figure without knowing at what time does the intake valve close.