I added a 32gb ssd drive and a USB Ethernet dongle as well (for 2nd interface).
The box has wifi, but no driver support from FreeBSD. My WIFI is supplied via a UniFI AC LITE.
1. http://www.newegg.com/Product/Product.aspx?Item=N82E16856164...
Seems the box you linked to has only 1 ethernet port. How do you connect to both WAN and AP?
Have had 0 problems with it so far.