The servo must be installed in reverse for good balance. To accomplish this, I first mounted the left side servo mount on the extra (left-most) holes already pre-drilled in the chassis from the factory. Then, I glued the right servo mount to the chassis with shoe-goo, and put a small piece of servo tape underneath the very edge of the servo that touches the chassis at an angle (for added security).
Once I installed the battery and electronics (including a 200mah rx pack), I added 14 grams of weight to the electronics side and the car was perfectly balanced left to right.
The car is still light...~20g under the ROAR weight minimum in ready-to-race form.