BWAHAHAHA no. You'll never get 15K miles out of a set of tyres on a GTR, hell I don't get that on the 911 and it's much lighter on the tyres. To be fair though, you'd be mad to buy the OEM tyres again as they're silly money, a set of R888s is cheaper I believe. Even better would be the MPSS if they come in the correct size. Brakes aren't cheap either, and being a heavy car it will eat those up too.
A GTR is a fantastic car, and the running costs aren't any worse than something like a 997 Turbo S, but it's all about the unknown costs as has been said. If you can extend the Nissan warranty that gives you bumper to bumper cover, then it's not something to worry about as you'll be covered. If you can't though, then that's when you're looking at the big bucks for carbon bits and expensive oily bits, which is why I have a warranty on the 911 because I can't afford to drop £15K if the gearbox blows up. Paying £1K pa for that peace of mind is worth it to me.
At £35K there's a whole heap of other cars I'd rather buy that would be as much if not more fun to drive, as you won't be worried about the servicing costs. Absolute performance isn't everything, not any more with The Man and his net closing in all the time.