well for a start xskape, whilst i agree with you that it does seem very low... would usually only expect old show cars to be at that figure, i would be certain it does would not have been doing anywhere near 15000km/yr (i persume your immature mind meant 15000 rather than 15km). most japanese cars are used far less than australian due to their dense populations and high road costs, not to mention articulate public transport means.
I myself bought a r32 gtr, it had its timing belt changed shortly before selling (as the jap owner provided proof).
All jap cars come with a lot lower kms than any aussie clown would expect, but i havent had a single issue with mine mechanically, so as long as you trust the seller, it probably is legit, if not close to the truth