Jerry's first car was never identified, but it appeared in an early episode (where he's infatuated with George's ex) to be an old run down 1970's era vehicle. In "The Alternate Side," his car (probably the BMW at this point) is stolen, to be recovered in "The Subway" as Jerry goes to pick it up from the impound. He gave up his BMW after the BO made it unusable. His first SAAB 900 convertible was stolen by Tony, his mechanic (The Bottle Deposit). It was not a turbo (witness Jerry and Elaine's brief excitement upon realizing the wreck at the warehouse is not a turbo, and therefore not Jerry's car). It is not revealed whether the stolen Saab is ever recovered, however, by next season, Jerry has an identical vehicle which may or may not be the same car (appearing in The Andrea Doria, The Susie, and The Pothole, to name a few). This one is ruined when Kramer puts his blood in the radiator (The Blood). Jerry receives a van from Frankie, which he hates, and which we assume he's sold (The Junk Mail). He has not yet purchased a new Saab, as Puddy's high-five resulted in Jerry's returning from the Dealership empty-handed (The Dealership).
I saw an earlier post, and felt compelled to clear all that up. Thank you.
-Kenny