I have an opportunity to buy a 93 fully loaded automatic saab 900s with 36,000 miles. Any reason not to?
The mileage is definitely a plus if correct. I mention this because sometimes SAABs have developed odometer or tripmeter problems and the speedometer head may have been changed out in the past. SAAB engines and transmissions are near bullet-proof. If driven right and maintained properly, they can easily go 300-400k or more.
The rest would depend on the price, if the car appears to be well-maintained, and has not been thrashed by an aggressive driver.
If someone is asking double value for it due to super low miles I might pass on it.
Thank you! I should have been clearer: the car has been owned by one person – my father – who has performed all the required maintenance and then some. I have always driven Toyotas, so I’m unfamiliar with Saabs, their repair costs, general handling and comfort.
They’re a bit more difficult to service as SAAB dealers, or anyone who knows anything about them, are scattered out further than Toyota dealers.
Normal maintenance repair costs are right in line with any other car. Often any specialty part that is needed, is not available except through the dealer, etc., can be found on eBay or a SAAB forum for a very reasonable price.
The fact that it’s known low miles and you know the history is a huge plus since it’s unlikely your father has been out beating that car into the ground.
SAABs do get ripped up a bit but speaking for myself, I like them. I’m an ex-SAAB tech, have owned a SAAB in the past, and currently own one. Just bought another one last week as a matter of fact.
Comfort and handling is superb IMHO. Drive one for a while and it may be hard to get you out of it. 
JMHO anyway, and hope it helps in your decision