if u are for sure eventually going to get a turbo, then yes, a DOHC head will work much better than ur SOHC 4g64 head. And i also agree with the fact that u should do these mods separately, that way, if/when something doesnt work just right when ur done, u will have a general idea of what could be wrong, cuz on the other hand, if u do it all at the same time, theres a lot more things u would have to check.

good luck with whatever u plan on doing