If the rubber is not the problem it is also possible that the door has incurred a dent. Have you checked if the gap is cause by something else or if it is the normal door and there is simply a gap because it is missing the rubber?
I am sure all of know that one of BMW's trademarks is the kidney grill represented in front of it's car. If you are wondering though when was the first time this was conceptualized and implemented by BMW, the answer goes way back in 1933.