I think that cliff detection would be a great help for this project. Avoid getting hit off the box more often than not.

You should make the robot closer to the ground so the robot has better balance and control. It wiil not fall as easily if it is closer to the ground.

Great steps for gear ratios.Ideas for changing the gear ratios faster?

Maybe, we could put the ultrasonic sensor on the NXT. We could put our fingers in front of the sensor right before the race would start. We could program the ultrasonic to go when our fingers are at a certain distance away from teh sensor.