Just installed Sync 3.4 unit in my MY2016 XLT. It replaced original Sync 2.0. I replaced dashboard USB/MMC-module with similar unit Joe Stewart has pictured upper in thread. It has some kind of quickcharge. I was also able to retain original armrest USB, since my XLT (manufactured in 11/2015) had long enough USB-wire from armrest console to APIM.
I paid about 350€+50€ (without taxes, shipped, from eBay), about same amount in USD. +50€ comes from the fact seller offered me EU-version of APIM, it has 64GB flash for maps, rest of the world-version is 32GB, since European map set needs more space. Usually EU-version is around 650€, so this was good deal. Unit came preprogrammed (VIN needed), and started working properly after installation. Kit included APIM, display, USB-hub, GPS-aerial (blue Fakra-connector), OBD-connector unit and tools for dismantling dash bezels etc.
Was it worth it? Definitely! Sync 3.4 is much easier to use compared to Sync 2. I have used Sync 3 too, 3.4 is big step forward. Sync 3.4 is much more responsive than 2.0, and now I have Android Auto too.