I noticed a slight whistle from the passenger side almost as soon as I picked my car up from the PCD in SC (2013 X3, DEc '12 build). It occurs around 80 mph and sounds almost like someone's nose is whistling. It is kind of hard to hear, but very annoying once you notice it. I took it to the dealer and they couldn't diagnose, so I came back and went for a ride with the technician who asked me to come back again when someone with "better hearing" would be around. I have a 2.8 with SAV package.
I want this resolved, but can't spend another day at the dealership making sure that they can hear it for something so minor in the broader scope of things.