My e39 is booked in to the dealer for the fourth time in 18 months for the rear door vapor barrier to be fixed. The dealer acknowledges that it's a "design flaw" in the car, and I've never been charged to have it fixed even though the car's now out of warranty. I know it's the subject of a TSB, but I'm now getting really pissed off with periodic soggy carpets and a damp, smelly car.
I'm just curious about whether there's some more serious or longer term fix for this. A "secret" warranty, or something like that?