I doubt a non turbo would make that much power? even then, it would still be alot for someone with less experience with driving on the roads. doesnt matter if you have been driving your mums falcon or not. full time driving, in all different conditions is what you need to learn in all types of cars, rwd, fwd, rain, blackice, dirt etc etc,
and if your uncle is an ex rally driver - you should be great out on the track - let us know which day you goto - would be interesting!
oh, and your prob buying a GTR than doing the engine swap in a few years, they'll be cheap as chips!