Buying a used car in Japan

Hi there,
Me and a friend are looking at traveling to Japan from New Zealand for about 2-3 weeks. We were hoping to buy a used car in that time and drive it round in Japan while we're there. Before arranging to export back to New Zealand. Is it possible for a non resident to buy, drive and then de register the car for export?. I've imported 2 vehicles to NZ through online auctions. But would love the chance to go purchase a car myself.

You need to proof you have a place to park a car when you register the vehicle.
You can buy a car without showing a permanent parking certificate but your vehicle will not be registered(=No number plate = Unable to drive on road).

http://en.wikipedia.org/wiki/Vehicle_registration_plates_of_Japan

Not realistic. You need an address in Japan and the parking certificate (this doesn't have to be your land but you need to contract a parking lot and get the certificate that the parking lot owner is letting you use that place; the parking lot I contract with asked my for 3 month advance payment, too). And the regstration process will take at least a week under normal conditions anyway.
I suggest you rent a car to do the tour and buy your car for export separately. I think its the only way it can be done.