Check out Corvetteforum, there have been a few bought/sold lately to get a feel for the market in the US. Values overseas are much different I'm sure. I copied this just for the info about the car ,not trying to promote it, just the most recent.
I'm selling my baby (one of them anyway). It's a Turquoise Metallic/Black 91 ZR1 with 46K miles. I am the second owner, and have had this car since late 1993. The car is spotlessly clean, and is basically like new inside and out. Many of you may already know this car. It was a "People's Choice Award Winner" at BG Gathering in May, 2002. It has chrome facory wheels with Bridgestone RE71s (easily 75% tread left), and an extra set of chrome rear wheels (with BFG Drag Radials mounted). The engine is custom painted by Maurice D. in Florida in silver metallic with red letters, and it also has matching red LPE Samco hoses and the red Samco air inlet duct. Car has the usual bolt ons; Watson headers, exhaust, MTI chip, LPE radiator, lowered rear, 4.11 gear. All stock parts are available (except radiator). This is one of the best looking ZR1s in the country IMHO (lol), and has been meticulously maintined and pampered. I really can't describe how good this car looks in writing, you just have to see it. I'm asking $25,500 to faciliate a quick sale.
There are others, along with pics. Arm up with some info/details and presented well to the owner, you may have a good deal. BTW, hood/front are common vette,doors back ZR-1 specific fglass.
That is how I bought my first vette. 5 years later I sold it for 2k more than I had spent on it the whole 5 years I had it(1976-1981). That was the best car I've ever owned.
Good Luck in your quest!!