My friend had a 280zxt from the same year, with ~120k miles, that he ended up selling to me for parts. The *only* real problem was the rust--the body was eaten all over the place, to the point where the metal around the left front shock mount was tearing a little bit further every time I lifted it up or put it back down on the wheels. I would definitely check for this, look carefully around and under the car for anything that's gone beyond surface rust, and if you buy the car, do something about any surface rust before it gets worse. Rust problems are unfortunately a trademark of the Z cars.
Mechanically beautiful though--the person he bought it from had maintained it religiously, since she worked for Datsun and got free service. The engine ran like a Swiss watch. I didn't pull the transmission apart, but I didn't hear anything about problems with it, and the fluid looked clean and didn't smell like burned clutches. The engine in yours might not be as good, but generally Nissan engines are some of the longest lasting around.
Other problems--the dash material often cracks with age, probably something to do with UV exposure. The one I pulled apart looked something like dried mud (it was the gold interior). The seats are often an issue, specifically the seams on the leather seats. In that car and my own '83 they've given out on the driver's seat. Aside from that I can't think of anything common, except for what I guess you would see in cars that age, little things like the windshield washer fluid level sensor going bad.
I hope this helps you out. If there isn't a serious rust problem, I would say go for it!
BTW, you don't have to post so often--posts don't vanish into the murk that quickly.