I like a lot of these solutions. I particularly like the ram mount up by the steering wheel. For me, drilling a hole in the interior piece is just not in the cards. My plan is to fabricate a custom bracket the slips between the dash and the head unit and mount in inside the dash. I'll probably put a magnet on the mount since I have a piece of metal on the iphone case. The magnet mount held up well on my Outback, but I never went off road with that.
For many years I utilized a mount that screwed into my CD player of my outback. That worked very well. However, when I recently removed it I noticed it deformed the foam inside the player opening.