The 2015 Mercedes-Benz GLK-Class is a 4-door, 5-seat Sport Utility, available in 3 trims, ranging from the GLK350 AWD to the GLK250 BlueTEC AWD. Upon introduction, the $39,900 GLK350 AWD is equipped with a standard 3.5L, 6-cylinder, engine that achieves 18-mpg in the city and 25-mpg on the highway. an Automatic transmission is standard. The $39,400 GLK250 BlueTEC AWD is equipped with a standard 2.1L, 4-cylinder, engine that achieves 24-mpg in the city and 33-mpg on the highway. an Automatic transmission is standard.