I am thinking about buying a 13lb Diva for my wife.  I looked at the technical specification numbers on the DV8 website, and the RG is higher for the 13 lb'ers, but couldn't really tell if it has the Diva core, or some other core.  Anyone know?

Thanks, good suggestion.  They are all pretty close, so it looks generic.

Don't quote me on this but when you get into lower weights, you can only change the density of the.filler material between block and cover so much to reduce the weight. It may be the same shapr core as the heavier balls but with a less dense material. This would make the ball less core heavy and could raise the rg. I know usuay 14-16 use the same block usually but to get to 13, I imagine the density of the core would need to change. I don't know if it winds up being a different block or just a less dense version.