The 2021 Mercedes-Benz GLS 580 is available as a 4-door, 7-seat sport utility. Starting at $98,850, the 2021 Mercedes-Benz GLS 580 GLS 580 is powered by a 4.0LL , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 21-mpg on the highway.