yep, high quality highways is right... except the speed limits are lower than home (they arent covering as much distance). see point 6 in my post about speeds! however, roughly half the country is pretty mountainous. but once again, a car like a stagea (or the majority of them) wouldnt have been pushed that hard on the mountains, as i think the typical stagea owner tends to be your average 40-something guy on the street. if youre looking at importing a stagea (as i will be eventually, when i get back to oz), it would be easy to tell if you should buy it or not. like one jspec, there is that red one with the gold wheels and mismatched bodykit. i would say that one would have been neglected (read: neglected; not 'abused'). however most of the stock (or close to stock) examples, i probably wouldnt think too long about buying.
im not trying to be a smartass or anything by preaching all this info to you but hey, if it can help then maybe its not too bad.
HOWEVER, one thing i am not too sure about re. driving conditions is the weather... of course oz is damn hot... but on the other hand, japan is damn humid (in the biggest cities).... for example yesterday it was only about 31 degrees, but no joke, i couldve sworn it was darwin, the humidity was so high. i thought i would be able to cut the air. would this constant high humidity in the summer and a little bit of spring have some kind of adverse effect on the engine etc? i wouldnt really know....
and i think one of the main things you need to worry about with a car from japan is the dashboard... they always have holes or adhesive pads where various things have been attached, eg navigation/dvd screens, cup holders, radar detectors, copious amounts of figurines etc