Originally Posted by Jack_88

225/55-17 is the OEM size for your car. You have the correct ones. The difference in ride and handling between yours and your friends car should be minimal. Since you know your air suspension works, and your tire size isn't at the extreme, the difference in ride indicates an issue. A shop will be able to scan the car and give you any trouble codes it may have, as well as inspect the suspension for worn bushings and joints. That's your best starting point now that the most basic things have been checked. If your steering is stiff, I would start with checking your power steering fluid level. It may also be due for a power steering fluid and filter change.

Originally Posted by Kebowers47

IF your auto is equipped with Active Body Control (ABC), the height is adjustable---pushing the button on the center upper dash once will raise it one inch, push it twice to raise it two inches, Or push it twice to raise it two inches. I suggest you get the 'build sheet' from MBZ customer service. This lists EVERY system/component your car was equipped with when it was built. There are many many optional features.