congrats for pulling the V8 out and swapping to the rotary! with swap work like that its no wonder the V8 didn't run either....
anyways, the car looks pretty good. the paint is BAD, but it seems ok under that. i vote for a return to white BTW
the subframe IS flipped, and they added a couple holes, but its easy to undo. the rear diff can hold plenty of power, if you don't launch the thing, if you do drag launches with sticky tires, its 250ish hp maybe a little more. 83 is small axle, 84-85's had bigger axles and can handle a little more power.
ReSpeed has all the suspension and brake stuff you need.
for the engine, a BP 13B in a 1st gen is FUN and not a ton of work