Congratulations on you acquisition. I have a 1995 960 and love the way it drives. You can install the seat heaters without changing the seats. The heaters are pads with heating wires built in. You can slide them in between the leather and foam bottom and back cushions. You will need the console switches, and the green relay that is attached to the seat bottom cushion. You should be able to find all these in a junk yard.
However by far the most important thing is to get the timing belt changed immediately if you don't have documentation that it has been done. It is due at 70,000 miles. If it fails, the engine will be ruined. You should change the tensioner, idler bearing and water pump at the same time. Failure of any one of the components is the same result as a failed timing belt. Not sure about your smell, but it could be associated with a failing timing belt component.
Hope this helps.
John