My original rear view mirror did not come with Homelink and compass.
I purchased one from eBay 80 bucks including shipping . I googled how to remove Rearview mirror.
It took me half an hour to install. It was plug and play .
Looks like you got a great deal. I can see lots of other BMW model mirrors with homelink, alarm, etc. for under $100 - wondering whether some of these can be made to fit in the i3?...