I have a ML 320 and would like to find and install a Merc Sat Nav. Would the neccessary connectors already be installed? Has anyone done this before?

You would be best served by pursuing an aftermarket solution. It is very unlikely that the wiring would be in the vehicle (some had it, but they are a definate minority). You would definately have to run wiring for the antenna (requires dropping the headliner). Additionally, the MB units compatable with your year looks like more of an afterthought than most aftermarket units. It's a little screen that sits on top of the dash. Not at all a seemless integration. The units will also be hard to find and you can expect to pay upwards of 3-4K after installation.

i just installed on in a 2000 ml, all we had to buy was the drive for the disc, outer antenna and the antenna interface mercedes sells a kit we bought with the drive, i can get you numbers if you want. in my case all the wiring was there, just had to buy and install the components. if you model has the mcs display all should be there. the das mounted unit was for the older ML's that had the smaller standard size Bose radio.
Ray
mercedessd@cox.net