I just bought a Zumo 396 after confirming it used the same mount as the 390. When it arrived I discovered the 396 does use the same mount but turned 90 degrees. This still fits the Navihalter, but the power cable is now blocked by the Navihalter plate. I'm going to have to try and cut out a slot to get the cable through I suppose. Just an FYI in case you thought it was a simple swap.
