I agree on both sides of the story, I lived in Japan for 6 years and I had a R32GTR. My friends all had GTR's as well. I'm looking at buying one locally only because I think the pricing is quite good here now, and I can check the car out myself. Japan has a lot of good R32GTR's but as said above you'll have to pay for them.
I speak and read Japanese and I regularly check the car sales online sites in Japan such as goo-net and car sensor; there are a few R32's for sales now up to the $40-50,000 mark. Now if they are paying that much for a good one what kind of condition do you think one that costs $15,000 is in? You can get good ones, but for the cheap prices everyone here seems to think.
Also check the the auctions, when a good one comes through the starting bid will always be over 2,000,000 yen ($20,000). Also be aware that most, from experience about 60-70% of R32 GTR's will have accident repairs from little stuff to half cuts. I spoke to my friend in Japan the other day to check a VSpec Vin for me and although the vin was a Vspec he said to watch out for niko ichi, sanko ichi, which means 2 car to 1, or 3 car to one.
Lastly, despite what KIRAS says, you can't always get a clean GTR from Japan, I've seen a lot of bodgy cars over there and for sale same as here. Either way, do your homework, have confidence in the car you want to buy and if it meets you price range, get it.
Lets put it this way, original k's under 100,000, no accident repairs, usual mods eg exhaust, chip, suspension, good paint, clean interior etc set aside about $25,000. That goes for OZ or Japan.