***SOLD*** Have a MMI Carplay/Android Auto retrofit box, by Premium Retrofit, for 2014 thru 2017 i3's that have the large LCD screen. Installs under the rear seat in 5 minutes, A long press of the Menu button activates it on-screen. Used for a couple of months in my 2015 - moving to a newer car that already has OEM carplay. $300 shipped. PM if interested before I eBay it.
https://www.youtube.com/watch?v=e_IfHWq2OKk