I would be torn between a modded R34 and a RX-7. It really depends what you want to do with it. Both cars are great when set up properly, but I am biased as I went from a 33 to 34. The RX-7 is a great car, but I have really only been out in one, Miguel's. That is a great fast car that is tuned perfectly and handles like no other. Tough decision though.
DRive it like it's stolen