I wouldn't want to drop any more money inside a prebuilt system that apparently has a lot of proprietary parts within it.
The case's back I/O shield is actually part of the chassis so if you'd like to drop in an aftermarket motherboard, you're going to have to modify the back with a Dremel in order to drop in your chosen motherboards I/O shield.
You'd have a better computing experience by dropping the ASUS N3150I-C inside an
InWin BP659 chassis.