A buddy of mine has a car stereo shop and had these Soundgate M2 car mounts. Another friend has had one in his car for about a year now so I figured I'd give it a try.
The first pic is of the "puck" that you attach to the back of the phone. It is held on by 3M double sided tape so it could be attached to the phone or to any hard case that you might have.
The 2nd pic is of the mount's base, again mounted with the 3M tape. You can bend the metal mount to mold to the dash better to get a better grip.
The 3rd pic of the mount installed. The mount comes with detailed photo instructions to fill in the gaps of my pics.
The 4th and 5th pics are with my phone on the mount. The instructions want you to mount the phone so that phone is partially supported by the dash, but it seems to be fine as it is, even on the heavily washboarded dirt roads around here.
Crutchfield has them
Amazon has them as well.
Next up for me is to buy a couple of cables, a right angle Micro USB and right angle 1/8" cable to make a snake to run back to my center console for power and the factory Aux in jack. I plan on using a piece of 1/16" dia rod to make a "mount" for the cables so that they don't flop around the dash when not in use. May also include a magnet to trigger the car mode.