Japanese Used car Auctions
Friend of mine who trolls on Driftworks linked me this with some cool cars, they have a trader link on there.
So my advice would be speak to the blokes on Driftworks as there actual importers from Japan on there. AFAIk the Yen is a bit wobbly at the moment, ive just bought an exhaust from Japan and it was quite a difference in price depending on exchange rate fluctuations
Having not done the car importing myself, but only considered it, thats the best advice i can give.
Oh, maybe give an importing company in the UK a call, you'll get the spiel of Yen is crap blah blah but ask the questions you need answered and im sure they'd be happy to help if they're nice