I found printing on its side to provide the strongest results.
Update, Since adding the tabs printing flat on its base is now the strongest.
after printing drill out the holes for the idle wheels with 2.5mm drill bit.
when placing in battery have it so you can pull the balance lead out the side to charge.
UPDATE: you can also have it facing out the back above the motors and glued there this way it wont get in the way for the tracks.
use 3d print pen or hot glue to fix the motor and switch and lid.
switch glued on above the motor.
all components require to have the plugs removed and soldered to fit insided.