The 2016 Mercedes-Benz SL-Class is available as a 2-door, 2-seat convertible. Starting at $108,050, the 2016 Mercedes-Benz SL-Class SL 550 is powered by a 4.7L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 24-mpg on the highway. The top of the line 2016Mercedes-BenzSL-ClassSL 400 , priced at $ 85,050 , is powered by a 3.0L , 6 - cylinder engine that returns an EPA estimated 20-mpg in the city and 27-mpg on the highway.