As anyone who knows who's bought one, the official griffin Car Dock uses a non standard mount size, making it difficult for those who do not like the standard suction cup mount they offer. (This guy) This guide will show you what you have to do in order to make it accept the standard size ball to allow you to use any mount you want. I used an iMagnet mount with my old S3 and loved it, but due to pain in the a$$ back on the Moto X, using a magnet style mount is not preferable.
This first pic shows the various mounts I had, disassembled, and what parts I used.
Upper left: Griffin official car dock.
Upper right: My old S3 mount, the iMagnet mount, and the socket piece I will be reusing.
Bottom: The Mountek Snap 2 mount I want to put the Griffin dock on. This mounts in the cd slot, a much better place to put it in my VW.
The only two pieces we really care about right now. The socket from the iMagnet mount, and the socket of the Griffin.