I bought a 2005 CPO 545i Sport with 17.5k miles on it last August. Ever since I've owned the car, I have noticed an annoying slight vibration while the engine is running in the steering wheel, even when the car is stopped and not moving. It was bad enough that I had the dealer replace the buttons on the left side of the steering wheel (covered under a tech advisory) because they were buzzing so much from the vibration. Does anyone else have this problem or know the cause of it ?