If Floyd bring his courage to the ring, I'd say he out-boxes them both, prime for prime. Both Shavers and Lyle could knock Floyd out just like Liston did, but I wouldn't bet on it if Floyd has his head on straight and believes he can win. His handspeed would be the difference in both of these fights and I can see him beating both over 12 rounds. Shavers presents the most danger early due to stamina, while Lyle brings more danger through the early and middle rounds.