ATI super damper?

lighter pistons may allow you to internally balance that thing and then (buy) neutral balance everything else (ie Superdamper is neutral) cast cranks were lighter than forged so they had to add material to have them balance to the same production rods and pistons so they had to add weight to the damper and flex/flywheel. Now that you have possibly lighter pistons, that may be closer to the natural bobweight of the cast crank and your externally balanced parts (cast crank balancer and flex/flywheel/convertor) would be not needed but it would have to be disassembled and weighed, then balanced anyway. If you buy neutral components (convertor/flexplate/damper) and have your crank internally balanced your good to go in the future.