I dont have one yet, but will be flying to japan to find myself something. SOON!!
I imported my 33 gtr myself using a japanese broker and buying 'over the net'. I was happy with the way things went, and brought the car over in good nick.
I am now looking at buying a 34 and for the outlay around the 4M yen mark, I will be personally inspecting the car, making sure its up to my standard Of course I will still be using a japanese broker (60,000 yen fees). As well as this I will have a well deserved holiday in japan.
Make sure you thoroughly research what you want to get, what your budget is, etc. Make sure you have a raw ready to go.
Other than that, the other guys have probably answered most of your questions. I would advise you to fly to japan to purchase this thing. 60+ thousand dollars is a large sum of money