What is a GLC 300? The GLC 300 is a premium midsize crossover SUV built in the Bremen, Germany assembly plant, and sold worldwide by Mercedes Benz. The GLC is built on the Mercedes Benz C Class chassis, and when properly equipped the towing capacity maxes out at an impressive 7,700 pounds. This AWD all wheel drive, turbo hybrid boosted GLC 300 blends the spirit of an SUV, with the soul of a sports car.