True, and it was on the extreme. Actually, keeping the counter weight was only adding onto the weight problem, and at that point, we could see out chassi start to bend inwards, so we went with extending the wheel base and removing the counter balance. Plus, we were already so slow, we were just looking for ways to avoid more weight, for the chassi and speed.
My team is currently deliberating [arguing] the same dilemma. I personally would use treads [even though I am part of a MINORITY]. They supply more maneuverability and more grip on most surfaces.
I would suggest trying both of them. As in try one and then the other, see which works best for your needs.
That is probably the best way. Treads and wheels can work differently in a variety of situations. Build the robot and then the wheels option should be available and easier to test towards the end of the build process.