I converted this one with 4 drive motors as it was an easier fit than gear diff axles. I don't like the gear motors for drive at all 4 corners as much as regular diff axles. I worked with my LHS owner who has a lot of experience with multi motor drive systems. We tried putting the motors in series and parallel. Series should be closer to all wheel drive but uses more amps than parallel. Series did work best but both ways allowed one motor to stop and it took the other motor to grab and start to stall before the other would take back off. All being said I think it will be fine for this conversion. I have to get a new ESC to run it on 12V but it did seem to work ok when I ran it on 7.2V and better when I plugged in a 12V battery. Surprising enough the cheap Tamiya ESC held up good on 12V for the short time I ran it.
Thanks for looking.
Travis