The GL-Class is essentially a stretched and widened M-Class to accommodate the three-row, seven-passenger seating. The GL debuted in 2006 to compete in the popular full-size SUV market, and it continues to set the bar for rugged luxury SUVs. The GL can haul up to 83.3 cubic feet of cargo inside and tow up to 7,500 pounds. The GL-Class comes with a four-year/50,000-mile warranty and gets an estimated 20 mpg on the highway; the GL320 BlueTEC gets an estimated 23 mpg on the highway.