The first Mercedes-Benz 300 SL Roadster exported to the U.S. cracks the top-10 at Scottsdale sale 1957 Mercedes-Benz 300 SL Roadster. Photos courtesy Bonhams. Based upon the racing car of a similar name, the production Mercedes-Benz 300 SL debuted as a gullwing-door coupe in 1954. Three years lat...