Team 34, that is a beautiful and impressive drivetrain. Out of curiosity, why did you choose to go with a differential rather than have one motor for each side and vary their speeds as you turn? It seems to me that if you lose traction on one wheel, you lose about half your power either way.
For video of an Ackerman-steering robot in action, look here:
http://www.chiefdelphi.com/forums/sh...ad.php?t=64389