Fernbank L.I.N.K.S. team 4468 has designed a quick and easy way to mount electronics on dual cim gearboxes. With hex holes so you can sync #8 nuts into the plastic for easily removal and reattachment of components. One of the models holds the digital side car another holds the bridge and power converter and the last holds 2 victors for the drive motors.
After 3D printing the parts put a #8 bolt through one of the holes with the head on the top side then put a #8 nut on it and tighten it all the way. It will be a tight fit but go up into the hex hole and eventually you wont be able to tighten any more. At this point unscrew the #8 bolt. The nut should stay lodged in the plastic. Repeat for every hole when you are done you can easily attach components. The holes on the sides are for zip-tying the mount onto the motors.