What is causing the floors in the back seat of my 2002 BMW 525i to get soaking wet whenever there is a lot of rain? At first, only the floor behind the driver's seat was getting soaked. Now the floor behind the front passenger seat is also getting soaked, altho' it's not as bad. Behind the driver's seat, the carpet right up to the "rail" (on which the closed door sits) is sopping wet. Mechanic detected a "plug" on bottom of car that was rotted out. Replacing it did NOT fix the problem - in fact it's worse! I went to topix.com and it seems a LOT of Beemer owners have had this problem - which seems pathetic for such an expensive fancy-schmancy car. I had 2 Toyotas previously - for 10 yrs and 13 yrs respectively. The one I had for 13 yrs had a moon room (as does my beemer) - but the Toyota never had this problem.
I would be grateful for insights!