I agree to certain extend, go up to the seller and offer what you think is reasonable and most time you'll be surprised. But having said that, 1 year ago when I was looking at buying my car, any 33GTR below 25k are just not worth looking at. I mean you can look at them but chance of you scoring a good mint condition one is much lower comparing to anything above the 26k or even 28k mark. I ended up paying something more for the N1 which I have absolutely no problem with at all.
Unless you're after something unique and special (N1, 400R or maybe colour etc), I wouldnt recommend importing. There sooooo many in the market now and prices arent that exp at all.
If you're concern with mileage, I wouldnt recommend you to even buy an import (maybe get a new car). I wouldnt even trust a logbook 100% (but they do provide some sort of evident). So long as everything is running fine and you like it, I dont see any problem with it. And seriously, how many Ks do you suppose they would have wind it back? Being more realistic, I'd say anywhere from 10000k to 50000k easily and dont tell me a good engine will blow up with more than 100000km on it. Having a logbook for a standard car (unless its a limited edition car) will mean nothing and to me, its not worth the premium you're paying (it doesnt help much with resale). Think about it, would you choose to buy a mint gtr without log for 25k or pay 35k for one that's got log?