I have been looking into doing the phone thing through my dealer. I ordered the SLK with every option except the phone mainly because the I had the v60, 5 years ago. Now MB is actually getting with the times and offering the v710. Well, not offering it yet, but soon, maybe. Anyways, Dealer quoted me $2500 for the phone and all the internal crap to make it work including installation. Then $500 more if I wanted to add voice control.
I found this online.
http://phdwebsite.powerpulse.cc/V60i Documents/my05.pdf
and his site also has other really good info, most I have not had time to read just yet.
http://http://home.earthlink.net/~phdwebsite/misc_phone_info.htm