Is it 4+3 or automatic? 4+3 manual trannys have problems with the overdrive unit... that would be the major cost item I would personally look at...
It would help to get a catalog from Ecklers or Mid America (
www.ecklers.com, www.madvet.com)... look at the prices of parts... the weatherstripping around the door glass etc. is a common problem, and costs a lot to fix... the leather seat covers, steering wheels, and well, all the leather items are expensive too. Tires aren't cheap, the bose stereos are notorious for breaking....
Keep in mind that C4 Corvettes are pretty reliable cars, I am just giving you some of the more costly repair items that are more common, I am not trying to scare you off...
Another thing to keep in mind when purchasing... mileage is everything on Corvettes... If you plan on driving it a lot, then go for one with more miles... the difference between a vette with 35k miles to 50k miles is big bucks, same goes for 50k - 75k .... get up to 75k, and the prices start to level off more. Just keep it in mind, because you may end up like me, with a low mileage car that I don't want to take anywhere... I drive my honda civic instead... I had way more fun with my '93... bought it at 59k, drove it to 105k miles... never worried about the value thing then...