I use logitech magnetic vent holder on my car. I put the magnet on the case and the vent holder is very sturdy. I'll try to take a pic on my lunch break.
I use this one...I like it quite a bit. I didn't want to put a magnet on my phone (clear case) and didn't want a windshield mount. Of course, I never use my CD player, so YMMV.
I would recommend the imagnet although you're going to need a phone case to hold the magnet and since it's a new release, there might not be too many for sale.
I got this for my S6 Edge and Iphone 6. There is a clip behind the mount to clip on the cords. It has a short rigid built in cord for Android phones. I chose this over everything else because of the clips on the back and the fact that it doesn't rattle when driving on bad roads.