Many BMWs have been using this system for a long time...it takes some of the stress off of the glass on the frameless windows when closing up against the weatherstripping. My 2011 GT has it, and so far, no issues. To get a good seal, there must be a fair amount of pressure of the glass against the weatherstripping, and lowering it slightly means after it is closed, the force is vertical verses horizontal, and less stressful, when it goes back up.