[Volasko]

My E90 had a drivers side door leak too. It would leak quite badly between the interior trim piece and the actual metal door down in the foot well near the clutch pedal. This would happen whenever It would rain and especially bad when I took it through a touchless car wash. I got it fixed under warranty at Maranello, all they did was replace the vapor barrier I believe, haven't had an issue since. Though they did my work in an afternoon and I got the car back the same day.