This is the back of the X carriage, and shows a several things. You can see that round metal locating pin I referred to when I discussed how difficult it is to attach the extruder. You can see the mating pads for the pogo pins. And you can see how the fan's output is split between the cool part of the extruder above the hot end, and the ducting on the extruder that blows onto the build. You can also see where those 4 permanent magnets connect to.

If you are REALLY familiar with the Rep 2, you will notice that the X axis belt is about twice as wide as the Rep 2's belt. We haven't had any issues with our belt wearing out, but maybe somebody has? Another difference is that the pulleys at each end are about twice the diameter, which will result in a less sharp radius for the belt to flex. It is hard to see because it's painted black, but instead of the two rods for the carriage to ride back and forth on like you see in most printers, including the Rep 2, the gantry is made of a piece of sheet metal bent into an inverted U shape. Attached to that are some glide rails that the carriage rides on. These type of rails are also used for the Y axis for the bed of the Z-Morph.