I'll add an odd quirk for our 2005 X3 - we went along for quite some time cussing at the way our keys didn't seem to work until we stumbled across an interesting observation. If I click the unlock on our X3 with my key *while the cars is already unlocked* in the garage before I drive the car my seat and mirror position will always get set up correctly. The same is true for my wife's key. Doing the same thing while the car is locked does not work.
We gave up on getting annoyed about why it didn't follow the description in the manual.
AKA AlanL on all other forums
2005 X3 2.5i - Mystic Blue
2010 328ix Sports Wagon - Space Gray