Somi, thank you so much for your very helpful post! I was able to export my addresses to my 2010 C300 Sport with no problem. As mentioned here previously, it is a little tricky to get the Bluetooth going between the Comand system and my Mac. One irritating factor is that the Option item next to UPDATE is grayed out when you enter the path via Settings>Bluetooth, I ended up going through the Phone menu first, then down to the Bluetooth menu, etc..., then when I arrived at the screen that listed UPDATE and my iPhone, the Options item next to UPDATE was available for me to click on, which then allowed me to authorize my external device (the MacBook). Then everything worked like a charm.
One big question I have is, do I need to do something with my addresses to make the Navigation work properly? (i.e. like you advised with changing TEL;CELL: to TEL;PRIVATE;CELL:) When I pull up an entry which has a street address, Navigation is grayed out.
Here is an example of an address from my vCard.vcf file:
ADR;HOME:;;XXXX Maple Street;Anytown;CO;XXXXX;
Should I add PRIVATE or WORK between ADR and HOME?
I would appreciate any help.