Regarding the odometer reading, from what I have read this was a major issue in the past when the cars they were importing and their subsequent profit by selling a low mileage car was higher. But now because of the costs involved (both in time and money) to wind an odometer back it usually isn't worthwile as the extra profit they would get is less than what they spend doing it. Also modern cars are a lot harder to do it to, especially with the switch to digital odometers. I guess dodgy computer boffins charge more than dodgy mechanics in Japan.
Also I notice the AA offer a odometer certification inspection: http://www.aa.co.nz/motoring/buyings...s/default.aspx
A few of the cars I have seen advertised state they have an odometer certification, not sure if it is from the AA or not though.
I noticed a few dealers advertise cars as being 'AA appraised', I take it this means that the AA has done a simple check to make sure its in good mechanical order and not a complete check inc. odometer readings and such?