To be fair its had what some would describe as a truck load of money thrown at it, so if you wanted to build an exact copy, it would set you back much more than the 35k asking price.
That said, it is £35k for a 2003 350Z, so the market will of course be severely limited to enthusiasts that fully appreciate exactly whats gone into the car (certainly beyond my level of technical know how). Of course such enthusiasts may wish to do this themselves rather than buy a "turnkey" highly tuned Z, regardless of cost.
All the best to Giles with the sale, but sadly in todays climate Id guess a £35k Z will be hard to shift, even if its had double that thrown at it in its lifetime.