Monti and Kevin are right.

Kevin - your car is more consistant with the batts forward because it has less weight transfer as you turn into corners. Becuase you run on carpet with good traction you do not need all the corner entry steering that you get from a rear battery position. In fact the rear position would make your car feel darty off power.

However, if you ever need more turn in...move them back. The increase in weight transfer increases front traction and coupled with a longer shock and some rear pod droop makes the car rotate harder into corners by unloading the rear tires.