I'm thinking about getting an '07/'08 335i, and am wondering if it's worthwhile getting one with the navigation system. As I understand it, it only works with a DVD--is that correct? If so, are updated DVDs available? I have two GPS units for cars that are easily updated from Garmin, so question the need for a built in system.
Also, does the BMW system work well? How is it for trip planning?
Thanks for any info.