BMC Alpenchallenge ACO1 upgrade (from 105 to Ultegra)

I have a 2017 BMC Alpenchallenge AC01 that came with 105 (5800 series) components. I've been slowly collecting upgrade parts as I find them on sale or for killer deals. The last of it, the crankset, arrived today and the upgrade will be done this weekend.

I am upgrading from 105 (5800 series) to...