[m^3]

Well a lighter robot will have less frictional force but also have less inertia... so I think the effect cancels out. As far as the car analogy, we are limited by friction, not power (did you see 2 vs 4 motor test on kickoff?). Therefore teams should shoot for 120 lbs since it reduces the relative effect of the trailer and other robots. Along with that the cg should be towards the rear wheels to help turn with the trailer.