Yeah, I agree with Frankenstein, if the motor goes out, you can get a new or rebuilt one on the cheap (probably less than the $3k he says though... I've seen 2JZ-GTE's for less than that!)
Another nice thing to remember is that the 2JZ-GE's are still used in current Lexus models! So the engine has a lot of future still.
And another thing to remember... Toyota knows how to build an engine! The last Supra I had, an 1985 NA, had nearly 300K miles on it when I sold it to get my current 1995 model, and that old MKII was still running STRONG!
I'd say go for it. Try to talk the guy down in price of course... but if the car's in good condition, straight frame, etc... get it.