The first Saab 900 was powered by an I4 engine. It was sold in a variety of body styles, including a 2 door convertible, 2 door notchback, 3 door liftback, 4 door sedan, and 5 door liftback. The liftback was just Saab's term for hatchback, and was by far the more popular body style regardless of the number of doors.
The tranmission on the original models included 4 speed automatic and 5 speed manual. There was also a 3 speed Borg Warner T-37 automatic.
The trim options included the GL, GLS, EMS and GLE. They were single carb, dual carb, and fuel injection,
There was little difference in the size of the engines on these 900 models. Some were turbocharged, which boosted power considerably.
Special models of the 900 include the Saab 900 GLi Gold, 900 Tjugofem, 900C, 900EP, 900 CD, 900 Enduro, 900 Lux, 900 SE, 900 Carlsson, along with several one-off conversions.
There are plenty of Saab 900s out on the used car market today. You can find them just about anywhere, but you'll get some great deals if you buy a used Saab 900 on eBay. You can also find parts to fit to your Saab 900, such as Pirelli wheels and custom body kits.