STYLON - Good point!
I have the luxury of a spacious dash so I mounted hub extenders to all of the ports on my DUDU7. So I can wait to figure out where any future devices need to be plugged. But, as you pointed out, make sure that any hubs you wire into your vehicle have Power Input ports.
I may still need to disassemble part of my dash if I learn that the power out of the back USB port is inadequate, but at least I have a hub which has a supplementary power port.