Make your power wires a length to where they can not be plugged in reverse or even to where the positive is not long enough to touch the negative wire no matter what.
If your esc is in line with your lipo and not to the side... no help.
But the Mugen does not need that weight in front for more steering... already has a ton of steering IMO. My esc sits behind the motor for a 50/50 weight distribution.