i see one obvious problem in your plan - using rockers and a cam, it may not work to your advantage having both and you would need to choose the cam grind specifically to suit your application or you can have problems with too much lift or coil bounce.
also a "sports exhaust" or whats known as a cat back exhaust is worth it, probably more so than extractors on a stock car.
if your rebuilding the engine i doubt you would re-use your current pistons, especially if your going to be using forced induction...getting some forged pistons would be worth while. i mentioned before about a thicker head gasket - this is how you can lower your compression ratio.
one key thing that you didnt mention is tuning...in your list, up untill the cam change you'll be right, after that you'll need to tune your car.
it would be wise and more cost effective to rebuild the engine at this stage, adding a bigger cam, forged pistons, have the heads ported (if you wanted to), o-ring the block and get yourself a copper head gasket.
putting the blower/turbo (i dont know what sort of forced induction your after) at this stage would save on tuning costs also, otherwise you'd need to pay for a tune after each mod, ie, after the rebuild, then again when the forced induction goes on.
something i also forgot is fuel supply, you'd want to get some s/c injectors, a rising rate fuel regulator, and also a better fuel pump to keep up demand with using boost.
in short you'd be up for a lot of money - quite the opposite of what you where asking for in your first post - "What are your recomendations for the best performance increase for minimal cost".
