Sorry for typing in English, my German is very bad
I have my ZR-1 for quite a while now, almost 8 years. It was imported into Germany from Canada, but with engine trouble. The German buyer sent the car to a GM dealer, who did not know what was wrong with the car and disassembled the entire engine! After reassembling the engine, the car was still running very badly and the guy, having 5000 Euro's of repair bills, sold the Z without it ever having had a German license plate...
After that, I bought the car from Andre Boer, a Dutch Corvette collector, who found out that a malfunctioning ignition coil (part costed around $100,- !!) was the problem. He replaced both coils and after that, the Z ran strong. After that, I went to Geoff Jeal in England, who checked the engine and installed a bottom breather K&N filter. I also bought a Flowmaster exhaust and besides that, the car is original.
This is the car in the showroom of Andre Boer:
The car at a meeting: