I run 5W40 Mobile 1 and my lifters are quieter. I tried 5W50, but at temperatures below about 55F, it is just too thick for a cold engine start - so I changed to the Daimler-recommended 5W40. Keep in mind that "0W40" sticker is ten or more years old now and that any MB or Chrysler dealer will put 5W40 in there, as that is what is recommended. 0W40 is approved, but 5W40 is recommended these days.

Of course, the injector clicking is never gonna go away.

Notice there are more 5W40s on the list than any other weight:
https://bevo.mercedes-benz.com/bevolisten/229.3_en.html