Ok , so have just got a 2005 s320 (w220 ) which had a v 4 sat nav disk in , as I px my old e320 which had a v6 disc they agreed i could swap discs . Very soon the comand started shutting down and restarting ! I have an upgrade dvd for the nav unit ( dated 2007 ) and used that weds eve, yesterday the system was fine , only shutting down once! Today its shutting down every 2 mins or so ! If I remove the nav disc its fine , except no sat nav of course. The v 6 disc is a genuine merc one and I used it in my e class for a good 2 years with no problem. I have bought a v 8 disc and am awaiting delivery of that , I understand there is a head unit upgrade disc available will that fix the problem? Oh and would that also give me eta visible as I had on my e class?