here is how i shortened my motor wires. left some on the orginal wire (6 mm) in the circuit board and exposed it to form soldering post. then simply solder the big motor wire to it.
people always complain about the fitment of the mamba but if u turn the esc it fits just fine. the usb cable is facing the motor, thus if i want to make a change ill just take out the motor. i think this is better as i don't make changes to the profile that regular.