I ordered mine balanced, and it really was good to go, nothing else needed. I do remember when I ordered the kit that the piston manufacture was undetermined (could be Icon, SRP, or Weisco if I recall correctly). I was fine with all 3, so I proceeded. My guess is it was to use as little heavy metal as possible in the balance (once rods were selected) to keep the price down. In my case, no heavy metal was required due to the light weight of the I-beams and the Icon flat top.