Not a Skyline but one thing to be wary of in the Supra are cars with less then 100,000km. It's very easy to pull the digital odo off and snip the wire that lights up the first digit. So a 180,000km car will only read 80,000km. There have been many tears on the forums when a "valuable, low k" Supra suddenly clicks over to read 00,000km.
Personally, unless its a real performance car (like a GTR) I assume most imports have done around 10,000ks per year, and I look for cars that match that number. I'd rather a 15yo R33 GTS(T) with 150,000 on the clock than a 15yo R33 with 70,000km on the clock. Low ks just scare me off.