Towing capacity is based off several factors, including mass of the vehicle, torque characteristics of the engine, the load capacity of the frame of the vehicle, the strength of the attachment points for the tow hitch, brakes, suspension/stability, transmission/cooling etc etc. Ford have designed the Falcon to tow as much as it does (in the past they had heavy duty towing packs as options, but it appears standard now) since a lot of people use Falcons/Commodores to tow boats/caravans etc. A Falcon isn't that much lighter than a Kluger though (~1700kg compared to ~1800/1900kg?), but they do have a big engine with lots of low-down torque (ideal for towing).