The 3 Liter Q60 engine would need revision. It was mated to a manual gearbox for the orange SEMA car. Looks like it needed a lot of parts.
I think if Nissan bother they should work to create a car smaller than the 370Z as the 370Z is quite bulky size wise and maybe get the weight down
Weight down to 1400kg and a twin turbo 399hp with a revised engine would be good. Any hybrid tech etc would drive costs up.
A dct auto development would cost money too. Maybe get a 7G/9G auto gearbox from Mercedes instead?
Either way look at the new A45 S. £49,000. Thats where the price will be if you start getting a development list together.