370z might be awesome John, but don't forget Ekona is always right and has a very informed opinion on anything, including the 370z vs Cayman vs TTRS vs GTR.
Having owned 370z, Cayman S and GTR in the same time for a while, my very humble opinion is go for the 370z.
The older gen 1 Cayman S has serious engine problems, looks dated inside and outside, expensive, but good handling.
The 370z with a few mods like exhaust, intakes or better filters, ARBs, coilovers, better brake pads and lines and some ECUTEK/UpRev tune can be an awesome car.
TTRS, won't t comment on that, never drove one, but judging by its cover, I don't like that book
GTR.... well, different league of a car, a supercar that happens to be a Nissan...