Just a bit of advice, go to one dealer for one issue. When you walk into the third dealership and told them this was the third time it was in for this issue they realistically don't care because they don't see it as you've complained about it before because to them you haven't, regardless of if thats right or not thats how it is. Don't keep going all over the place because you're not happy. Clearly you're not happy with any of them but you need to find one to stick it out with until they get it fixed. Going from one dealer to the next saying so and so from such and such dealer couldn't fix it so i'm now here isn't going to get you anywhere.
You need to ask ONE dealer (probably the one that verified) to call their FSE (BMW field engineer) and have him come look at the vehicle and work with the dealership and if they can't fix it then maybe you have a case for a buy back, but you're never going to get anywhere going from place to place and badmouthing everyone.
that said I understand your frustration because the dealer that duplicated and tried to fix it 2 times should have called their FSE already.
Good luck getting it worked out.
P.S. why did you post a Z4 issue on a 7 series forum??? IDIOT
