The Mercedes Benz GLS is offered in four basic flavors, each defined by their engines. The base model utilizes a 3.0L V6 turbo that runs on diesel. Capable of 255 hp and a monstrous 455 lb-ft of torque, the GLS350d should use significantly less fuel than any other trim level. The GLS450 also uses a 3.0L V6, though this one runs on gasoline and ups the number of turbochargers to two. It makes 362 hp. The GLS550 has a 4.7L twin-turbo V8 and produces 449 hp and 516 lb-ft of torque. At the top of the GLS hierarchy is the performance oriented AMG GLS63, power gets upped to 577 hp, produced by a 5.5L V8 with twin-turbochargers. All GLS models use an advanced 9-speed automatic transmission which sends power to all four wheels. Being a full sized luxury SUV means that GLS comes very well equipped even with no options added. Standard interior features on the GLS350d include MB-Tex seating surfaces, a power driver's seat with a memory function, heated front seats, shift paddles, an 8-inch high resolution touchscreen monitor, eucalyptus wood interior trim, Bluetooth connectivity, a five year subscription to Mercedes-Benz' mbrace Connect system, power folding rear seats, power folding side mirrors, a power tilt and telescoping steering column, a power liftgate and a power sunroof. Other standard features on the GLS include AIRMATIC suspension, 19-inch wheels, an active brake assist system, crosswind assist, a rearview camera and 11 airbags. Of course it wouldn't be a Mercedes-Benz if the option list wasn't long enough to get the vehicle exactly as the buyer wants it. A parking assist package adds a 360 degree camera system as well as a system to park the vehicle with minimal input from the driver. A Premium 1 package adds multicolor interior lighting, a blind spot detection system, keyless entry and start, a memory system for the front passenger, SiriusXM satellite radio and better smartphone integration with Apple CarPlay. Stand alone options include a heated steering wheel, a Bang & Olufsen sound system, an air purification system, a rear seat entertainment system as well as a trailer hitch. All GLS models are capable of towing up to 7500 lbs with the trailer hitch.