I did the KUDA mount with a ProClip device holder for iPhone 6 (for small to medium cases) and plugged the lightning cable into the port under the armrest. It works great and the holder will adjust to my different cases except the lifeproof (too bulky). FYI: it was definitely expensive for both parts.
http://www.kudausa.com/bmw-4-+-m4-f3...ack-a1880.html
http://www.proclipusa.com/phone-hold...666-19733.cmsv
I apologize for the photos, I was tired and too lazy to get my real camera to snap pictures with the iPhone in the cradle.