Diamond is not too far from my house. They make some great pistons, but in all seriousness, for the money the KB/Icon forged pistons are a far better deal for the momey and IMO, just as good.
figure 500 dollars for the icon vs the 800+ dollars for the diamond and it's a no brainer to me. The diamond is slightly lighter is all, but that is by far not enough to make me use them over the icons.
That extra 300 bucks can go a long way elsewhere.
If I was building something in the 650 plus hp range with better rods and crank I would probably spring for the diamonds. But for the 450-550 hp stroker, the extra money on diamonds (again, in my opinion) is a waste of money. This is especailly true when people are making due with the hypereutectic alloy pistons in the same 450-550 hp motors.