You can paint your motors. I used 1:1 high temp engine paint on my castle motor. I've had no problems what so ever.. just make sure you don't use paint that has to be cured at high temps to seal the paint.
you can pull the shocks out and add "fuel tube" pieces on the shafts to "lock" them in place fully extended....
....as for the motors?....they are identical...just different color/logos