I almost believe that Brunswick does not need an actual particle pearl ball because two of their pearls, the original Inferno and the new Intense are so strong in the mids and the backend, that, for all intents and purposes, one might as well consider them to be particle pearls. (NOTE: I am not saying they are particles pearls; they just seem to act that way.)
I see a more significant gap between the Slay/R (too weak a cover) and the Power Groove pearls (too high an RG) and the next stronger level pearl resin, the Inferno (or the Intense). Now that's a gap you could drive a truck through. The Red/Black Monster used to fill that role.
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"We get old too fast, and too late, smart."