I agree with the spur gear barrier, but I think the CRT.5 motor mount has a "bulg" on the side of it that helps keep things from contacting the spur gear. It would hit the motor mount before the gear, but for saftys sake I would still put something in there myself.
Sweet looking build though. Wheres the ESC?
I can't decide if its more fun
to make it...
or break it...