Hi Mike,
The xEM comes pre-programmed in EM mode so it probably won’t be necessary to get the proxmark3. However, if you do get one, the more expensive kit version that offers you the ability to swap antennas around at will is the better option since the xEM’s geometry is an issue with most antennas… we are exploring creating a specific antenna kit for the proxmark3 that is designed to work well with the xEM.
As for installation, I believe it’s just lack of customers in that area. We partially rely on customers to expand our partner network, so we hope you are able to follow the guide and find a local professional, and that they eventually become a partner.