Don't worry man,
this was our robot in our rookie year 2 days before ship. Turns out we were about 40 pounds overweight as well (actually about 30 when we realized we forgot to take out the battery), but we managed to get it all together before the end of ship. Our best methods of losing weight were to remove some drive motors, replace some thick aluminum bars with thinner stuff, and of course cheese holing well into the night (literally!)
Best of luck, I'm sure that you guys can get it done!