Mercedes around so I was able to test it.
It works -- the car's mediainterface played the music without much effort — but there are a couple of caveats ... back aren't recognized for some reason.
2. Once inserted, the icon in the mediainterface lights up in the list to confirm it is seen.
3. There ... initial loading that takes less than a couple minutes
4. The navigation in the mediainterface is really primitive, it seems to lack basic folder forward / backward / artist & album
options