Originally Posted by ljohnson

You don't need expensive tools to get the weight balance mostly right - just try lifting the car at the center from both the front and back ends with something narrow, like a hex driver. Use the shaft to line up the center if you don't have a center point marked. When you lift, the side that lifts first needs more weight.

Alternatively you can weight the parts going on the right (battery) vs the ones on the left (electronics and motor) and go from there.

Misbalanced cars are really hard to drive...