I was in Sydney on the weekend and hadn't yet read this thread, long story short had a look at couple of private seller cars which I passed on.
While in town had some time to kill so got on trusty old google and found all of these Import dealers along Parramatta road... One even had "Sydney's Most Trusted and Respected Import Car Dealership!" plastered all over their website hahaha.
Sat in the R34 S1 on Sunday and the salesman went on to explain how its not one of the 200 built and that the previous owner had bought the car stock then when to Nismo in japan to have the goods fitted, to be honest looks like a nice car however I doubt very highly the validity of the Km's and the asking price seems ridiculous vs the quality of the car. The Interior was not from a "very well looked after" 47xxxKm car, steering wheel is covered in scratches, seat bolsters weren't worn through but they did seam a little age softened, the front bar lip has a crack in the drivers side plus the usual scrapes, the window and boot seals appear sun damaged, and the paint work seemed to have had a pretty poor cut and polish.
I am on expert by any stretch but after reading this and seeing what I have best to just keep squirrelling away money until the right one comes along, whilst collecting as much advice and knowledge possible along the way.