Originally Posted by BabyMakingWeather

Australia does not have enough roads to require a DVD - so check, as I think you'll find that the second map is a CD too. The two maps might be different if one is PROFESSIONAL and the other HIGH, but this sounds unlikely - i.e. the maps might well be interchangeable.

Sensis will never add speed cameras, as they will be out of date as soon as the map is published. However http://pimp-my-nav.com can add speed cameras to the Australian maps, while speed camera POI information is available from a number of sources including http://pocketgpsworld.com and http://gps-data-team.com

BMW Australia changed to MKIV at the same time as the rest of the world.
You need a MKIV nav to add speed cameras, so that might be a reason to upgrade.