this robot can stack, knock over boxes and go under the bar.
we also have two gears (hi/low) to choose from. In low it is super-torque, it can pull a car (camry) and a van tied together. In high gear, it is super fast. The whole stacking/lifting mechanism also tilts all the way back, so that the bot can go under the bar.
in addition to the compressor, you should also consider moving your light inboard of your robot. I know that our robot, and many I have seen, have metal frames and appendages that will strike the light during a collision. Perhaps you should consider getting some lexan or thin aluminum and putting a casing around your bot. How close are you to the max dimensions