i put 2 pins in the top of my starter box then drilled 2 corresponding hole in every chassis i have it worked on mbx6 mbx5t losi buggy and a turmoil. this was on the ofna chrome top with 1 12volt motor it works best if the chaasi is bare to line everything up i also clamped the box top to the chassis so i could line it up perfect .i have not noticed any problems from the holes in the chassis. that was my solution to the same problem you are having . later