Please bear the following in mind

At the onset of winter, have your vehicle winterproofed at a qualified specialist workshop, e.g. at an authorized Mercedes- Benz Center.

Observe the notes in the "Changing a wheel" section

    See also:

    Cleaning the steering wheel and gear or selector lever
      Thoroughly wipe with a damp cloth or use leather care agents that have been recommended and approved by Mercedes- Benz. ...

    Cargo & Towing
    When properly equipped with the optional trailer hitch, the GLK350 is rated to tow up to 3,500 pounds. ...

    Premium-grade unleaded gasoline
    To ensure the longevity and full performance of the engine, only premiumgrade unleaded gasoline may be used. If there is no premium-grade unleaded gasoline available and regular-grade unleaded ...