I created this magnetic phone mount for P1 Volvos ( C30, S40 & V50 ) It utilizes the magnet portion of a vent-mounted magnetic phone holder (see link below). Remove the vent clip portion and screw it into the 3D-printed mount. Voila, now you have a better-integrated phone holder that won't block your vents.
Similar style phone holder to the one I used
The author marked this model as their own original creation.