Change my tire size..

Check with Mercedes first to see if changing the size will mess with the traction control and ABS systems. Some vehicles are very picky about tire size and tire size differences front to rear.

Bare in mind that changing the wheel size will make the speedometer give false readings because the speedo is specifically calibrated to the standard wheel and tyre combination. There are websites where you can input your original tyre size, tell it what size wheels you're changing to and it will tell you what size tyres you need to fit for minimal speedo error.