[Richsgt]

With the way the game has been played out recently, i would also advise to add the CIM's back in and take the weight out of other components..eg find anything thats steel and put hole patterns in it.
One of the main items to consider though is that you designed the robot to drive a specific way, basing the position of your motors, gears and even wheels on an ability to generate enough power from the motors. When you suddenly reduce the ability to produce that output by ~50% the design itself changes in varying ways. Eg if you have a 6 wheel drive system, having 2 motors instead of 4 reduces your ability to accelerate out of a jam.
Also by removing the ~10lbs from down low(I'm assuming the drivetrain is based close to the ground) and leaving the weight up higher your CG has just shift upwards by a couple of inches meaning you can tip more easily and and you remove the weight over the wheels altering the overall performance(maneuverability, pushing power etc). Then again as well we designed, an re-designed and re-designed(and a few more in there) for a powerful drive which was one of our top priorities early on.
Then again you might not have an option but I'd advise against using one side with 2 motors and another with 1 as that could lead to more problems than anticipated, but i don't know how your drive is set up so cannot say it would be totally bad, heck it might even work out ok. Definitely look to remove from other parts, even look at using smaller chain, it might break a little more often, but cutting the chaing size to one 80% will save you that much weight over the entire run. Good luck