I bought a drop in K and N filter for my 2012 535i. And when I went to the dealer to ask about something unrelated I told the service guy I installed the K and N. He said he didn't recommend them because the oil from the filler can mess up a sensor in the airbox. He said he has seen it happen several times. He didn't seem like the SA that hates modes. Quite the opposite. So I took it out and put the stock one back in.
Anyone heard about that ? It kind of makes sense. The K and N is kind of oily when I removed it from its box.