The amplifier version is about the inputs.
If you use RCA cables to connect your subwoofer then "single ended" is the option to pick.
If you use XLR cables to connect your gear, then get the XLR amp.
Neutrik connectors allow you to disconnect the drivers from the amp to make them easier to move around.
The amp box is just the option for a decorative cut out on the side of the box that holds the amplifier.