I asked about this on this board prior to ordering our X5 last summer. IIRC the reference to "single drive" has to do with NAV. IOW X5s "equipped with a single drive" do NOT have NAV. The lack of reasonable PDC volume adjustment contributed to our not ordering the Tech package, even though we really wanted the rear view camera.

FWIW since our X5 does not have NAV, we can adjust the volume of the seat belt gong. BUT as I reported in my previous post, even at the lowest settings the gong is still annoyingly loud.

Funf Dreisig