The 2019 Mercedes-Benz GLS 550 is available as a 4-door, 7-seat sport utility. Starting at $95,750, the 2019 Mercedes-Benz GLS 550 GLS 550 is powered by a 4.7L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 19-mpg on the highway.