Make sure it has a full Nissan (hopefully HPC) service history but like the 350's, no point in handing over your life savings for Nissan servicing post the expiry of the warranty period as there are good independent alternatives out there.
Aside from has been said above, one issue that I have seen raised by different members is the alarm going off randomly and I don't recall feedback as to what the causes were - although it may be 'operator' errors such as windows left open etc as opposed to faults. But worth checking as best you can.
A set of tyres can be picked up for less than 1k now, in fact I have heard a set of the favoured Michelin Pilot Super Sports can be had for around £800 now - I would have saved over £250 compared to the price I paid in October 2013.