Just bought a 335i M sport with the alcantara sport seats and noticed that on the driver side the left lumbar support (bolster) has sunk a bit lower than on the right side. It works ok, but should be 1-2 inches higher. It actually leaves the cover fabric a bit loose right on top of it.
This could be just a matter of adjusting it's position, but is there a diy or some basic instructions what to do? Removing the cover would be a start...