Just get a professional to have a look at what you want to buy, compression tests etc etc, body panels line up etc.etc and you know you half way there, then just look after it and hope for the best, not much else you can do, sports cars are usually made with good strong bits, so if not fiddled with and serviced properly, they'll last long, check the radiator fluid, should be brightish green not muddy brown, just one indication it was serviced properly, something lots of people overlook.