I believe that the A4WD1 robot comes with the new 12vdc motors unless you secify a different voltage motor.
My A4WD1 came with the 12vdc motors and I am using two 6vdc batteries in series to provide 12vdc for the motors.
I am also using a Sabertooth 2X10 R/C motor controller in place of the Scorpion HX.
The Scorpion HX might not have enough current carrying capacity for the new 12vdc motors.
Just a thought.
If you are going to send a Robot to save the world, you better make sure it likes it the way it is!