[jrich4411]

I had similar issues with my first '06 ///M. It started with strange electrical issues. One day I was driving and the nav screen shut down and the radio simply shut off. I pulled over, restarted the car several times but the nav screen would not pop up and the radio would not turn on. about 15 miles down the road suddenly the nav screen popped up & radio came on entirely on their own. sometimes the nav would cycle up & down 3-5 times in succession.
the issue progressed to the point where the "idiot" lights would turn on & off at random. sometimes all of 'em, sometimes just a few.
Then, I started having the dead battery issue. would park the car late in the evening & by morning - some but not all mornings - the battery would be dead. I even went to the point of installing a disconnect on the neg terminal.
This was all with about 2 months left in the season, so she got parked that way for the winter. Come spring, I finally brought her down to the local dealer (an hour and a half away from me). The intermittent electrical issues were an after market remote convertible top module from Reinhold Engineering I had installed. That was removed and intermittent issues went away.
Now for the dead battery - my radio was continuously pulling 2 amps of power - never let the car go to sleep mode. This drained the battery overnight. It took a month to get another radio - the parts supplier kept shipping the wrong model (one NOT integrated with the nav). even had one shipped from Germany. In the end they sold me the radio at half price to make up for the 5 weeks it took to get it. But in the interim, just disconnecting the radio cured the dead battery issue.
good luck!