However, the part holds so much that it can no longer be solved without the ventilation grille to take out completely and with tools (pliers, screwdriver) to release the two holding arms from the vents, which you must then choose whether you prefer the holding arms, or the blades damaged ventilation grille. For me it has left to a mounting arm and ventilation grille irreparable traces. I had it mainly for car purchases because the navigation systems from BMW and Audi seems to me not very confidence inspiring.
Therefore, I can only advise you to use this bracket if you want to use them only briefly. Once grown, it is connected to an immense effort to solve them again without leaving damage.