If I'm assuming correctly that you're on a budget (correct me if I'm wrong) what I would do is paint it the original color (or another stock Datsun color), restore the interior to stock, and throw in an L28ET, which I expect will make enough power to satisfy you, relatively cheaply. I think the Watanabes you talked about would be appropriate if they will fit without flares.
That's just me though. Ultimately it's your car and your decision.