I have to believe it's a toss up between Del Warren's Morpheus core(s) and Mo Pinel's Colossus/Hercules/Mayhem core(s). These seem to be the trickest and provide the most hook and backend.
H - O - W - E - V - E - R,
The most complex is not always the best. In the world of bowling balls, it's not the core, but the match-up of core and coverstock that is the most important. Chicanery and finnesse will overwhelm brute force every day of the week ...
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"Just because you can do something does not mean you should do it."