There are times in a cars like when you can get away with certain things. The ideal is that you buy it right before it’s major maintenance points so at least you have time to change those major components. Drive the car and see what needs to be done. The most important ones on a Z32 are every 60000km for the timing belt, and every 120000km for water pump, etc.
There’s really no way to exactly judge based on KM for a car like this. Things just break out of the blue (Part of the reason why it’s an impractical, temperamental car)
The engine is always a weak variable. It can break at 20,000K or 200,000K. You can only really tell based on how the car drives, the condition, user history and the seller themselves.
I can only tell you that I’ve never had to buy a car with such a mixed pot. I could only trust my judgment and that of my fathers to get a clean car. A true father/son effort with miles of patience.
If we both end up at the next meet I’ll explain it all to you.