Don’t do what I did with my R320 diesel. I had a rush of something to the brain and filled it up with £100 petrol. I have a very good independent MB garage near me. They tried symphony the tank but it appeared to be Thief proof. So I agreed to them removing the tank, this was my second mistake! To remove the tank, they needed to remove the rear seats to remove the carpet. I don’t know what sort of adhesive MB used to glue the carpet down, but to say that it was excellent would be an understatement. It took them all day to do it, I even had a try myself and made no progress at all. I said that two of the mechanics could have the petrol telling them that it would be tainted with some diesel.
Anyway to get back to where I started it cost me £100 in petrol, £114 in diesel and just under £1000. Safe to say that I triple.check what I put in my CLK 500.
Moral of the story don’t be an idiot like I was and triple check what you are putting in your car before pulling the trigger on the pump handle.