A modern M.B. is not a friendly DIY vehicle.
There is not even a dipstick to check the oil level.
Everything is run by computers and electronics.
So, make sure you have a friendly independent or dealer with reasonable service costs.

I had a 2004 CLK 240. (auto trans) Ran it for 35,000 km's from new, serviced it twice at the stealership. The transmission developed a leak. The stealership wanted an ungodly amount of money to repair the leak. I had the leak patched up at an independent for $ 500.00 and sold the car.

I never reset the trip computer for overall MPG while I had the car. Over 35,000Km.s averaged 10.5 litres per 100 km,s - city and country. Around 30mpg (imperial gallons not U.S.)