I think part of the reason (or at least an upside) the 2355s weigh what they do is they weigh so close to stock pistons you could swap them out and your balance would be no worse than the shoddy balance jobs these engines came with from the factory.

Some guys claim the ligher pistons would produce a better et. I have a hard time seeing a 440 needing to rev up quicker down the strip than a heavy piston 440 would rev up in neutral.