Just went through the dealership having my X3 for four days, after discovering water (again) in the passenger side of the cabin. In June, when I discovered water in the passenger side, they said it was a crimp in the drain line, and replaced it. This time, they had the car on the "water simulator" almost all day and could not replicate the problem. Service rep said he thought it was the seal for the sunroof, as there was a slight gap. Seal replaced, sunroof aligned. Told him the proof would be over the weekend, as we were expecting severe storms. And just as I was afraid of, after a deluge of about half an inch of rain in 30 minutes, I went out to check the car, found the water in the rubber floormats, and the underlying carpet soaked. (I would have sat in the car during the deluge to determine the origin of the water, but as there was a tornado warning in effect for my area, decided that wouldn't be prudent.) Back to the dealership... need to determine the cause... drain holes clean, supposedly drain line straight with no crimps... can't keep paying $500+ for them to "dry" my car. Suggestions?