I have found with the plastic lipo tray I can use the weight I need to add to balance the car left and right. I have added most of the weight on the right side with the light receiver. I run the sphere TC ecs that is heavy to begin with on the left side. I am also running the KO 2413 servo that is light. I would rather have a full size servo for added weight. I am also using a Core 5000 lipo. Over all I think the car handles best with the lipo and plastic tray. I have my car at 1425Grams with the body. And have the car balanced very well left to right. Oh I almost forgot. I have 2 25mm fans on the rear for more weight.