I copied what appears below from Rotary. Basically with the three stage arms you can lift just about any car out there and that lift with three stage arms can lift up all Mercedes vehicles.

"In order to safely raise a vehicle using a two-post surface or inground lift, it is critical that the lift arms make contact with the vehicles designated lift points. Failure to do so can damage the vehicle and put the technician at risk. On some vehicles, especially those with shorter wheelbases, wide vehicle track widths and/or low profiles, the recommended lift points can be difficult or impossible to reach with standard two-stage lift arms.

Rotary three-stage arms have three telescoping sections, providing a greater range of extension and retraction than any other lift arms. As a result, they can reach a broader range of vehicle pick-up points. This increased arm sweep has made the Rotary Lift three-stage arm package the preferred lift application of many vehicle manufacturers.

Some of the manufacturers, including Honda and VW/Audi, are insisting that their dealers use only Rotary Lift products with three-stage arms, says Mark Fitzpatrick, Rotary OEM account manager. They count on us to insure that their dealers have the right products to lift their vehicles safely.

Standard lift arms do not retract inward far enough to reach pick-up points on the Corvette, Cadillac XLR Roadster, Saturn Sky or Pontiac Solstice. Technicians at the GM Service Operations Garage in Warren, Mich., confirmed that the SmartLifts with three-stage arms installed there can properly lift these vehicles. Extensive testing has also found that only three-stage arm lifts can pick up all Mercedes-Benz vehicles.

Lifts with three-stage arms can improve technician flexibility by enabling them to move from one type of vehicle to another, such as from an SUV to a compact car, without making a lot of adjustments or having to stop and re-spot the vehicle."