Lol, my Dad has always told me to beware of used car dealerships.
Just get Iron Chef to handpick you one going through auction in Japan....thats your best bet if you want an immaculate vehicle etc.
From what I know, the white r34's are a bit less sought after in Japan, with colours like Bayside Blue, MNPIII, Black commanding a premium.
I regularly scan carsales and gumtree and most Skyline GT-R's I see are in rubbish condition with non-genuine km's. The problem is the local market has been flooded with absolute shit (thanks to some dealerships).