No particular demand.
$18,000 - $20,000 is a decent price for a R32 GTR these days, but it doesn't hurt to pay a bit more towards the mid 20's and get a very good condition one.
Having said that, it is a 20+ year old car... Things will need replacing sooner or later.
I have heard of 6 foot tall if not taller ppl sit in S13 Silvia's / 180SX's.
The seat will go back quite far, just don't have anyone sit behind you and you'd be fine.
Ppl always say AUS dealers wind the clock back, unless they have Log Books to tell the service history...
Only way you can tell is the condition of the car and get a mechanic to check it out.
+ The Import Dealers reputation is on the line if thing don't match up.
If a car looks like shit and done very little Km's, then there is something wrong.
Either way, be prepared to spend money to get it back to a good standard, service it every 5000 km's, keep on top of things and the car will take you a long way.
I believe most GTR's would either be a weekend car or a track car.
Due to Japan's dense population, most would take public transport and don't want to put up with the pike hour traffic, especially in a GTR
That's how I see it...