There were three generations of these cars. The first was from 1990 to 1993,
the second from 1994 to 1996, and the third from 1997 to 2001.
These cars featured V6 engines, with either a SOHC or DOHC. The top model was the DOHC Twin Turbo. Transmission choices included a 4 speed automatic or 5 and 6 speed manual.
These cars were full time all wheel drive vehicles with four wheel steering and some of the best aerodynamics of their day.
One of the reasons sales of this car dropped were rising prices. As the price of the car went up with each year, the features that were standard went down. It was just hard to justify buying a new car that was not as good as the previous year's model.
These cars were sold in the American market as both coupes and convertibles. They are still very popular with some car enthusiasts, and there is an active community of people modding and customizing these cars. If you want to buy a used 3000GT, I suggest using eBay. There are many listings on there, some of them for already-souped up models and others all original. Either way, there are parts to fix any problems also listed on eBay.