Bought the car off a used lot, Car fax came up with no problems, got rear ended, bondo littering the ground, car repaired, drove home oil light lit up, topped off oil, 100 miles later, car sounded like a diesel truck, dealer diagnosed as a sudden turbo seal blowout. $4000 later the car ran like new, 70,000 miles later exact same thing happened, dealer baffled by this. If it was not for the turbo, which is standard on all Saab's, I would buy another one.
Handles well, very comfortable.
Sorry, but when you got rear ended your exhaust most likely took a hit too. This could possibly cause the turbo problem you mentioned seeing as how the turbo (and its "seals") is part of the exhaust system. It does no one any good to pan a car for an issue like this, apparently your mechanic dropped the ball.