Really glad I consulted this forum. Was getting the reported droning sound from my 2007 Passat Sport. I was absolutely convinced it was a wheel bearing and actually had it booked in for a replacement. Was a bit hacked off as the car has only done 40k miles. The car was due an MOT before the work could be done and I had a couple of new tyres fitted. Guess what? - Droning noise has disappeared. Saved me some serious dosh. Moral of this story - Try rotating/replacing tyres before looking at wheel bearing. If you aren't convinced, try Googling 'Passat tyre sawtooth problem'. What have you got to lose apart from money?