I think the biggest key that no one is talking about is the health of Shaun Wade. Day's comments during his presser yesterday were less than pleasing to hear: "Day said Shaun Wade is “getting a lot of rest” as he recovers from the injury that kept him out of the Michigan game and forced him to leave the Big Ten Championship Game, but he's “been doing a good job” and they'll get a better idea of his health in practice this week"
The having a better idea of his health in practice is not a reassuring sound - seems like one of those not fully healed injuries that one hiccup during the game/practice will put him out. I do think he plays, but would wager he would be more in the 80% health range, which will be a key factor in the game if true. We will need all of the CB's healthy and then some to be able to slow down Clemson's WR's - this includes the backups getting some reps in certain situations and confidence against them as well.
Depth and contribution at all levels will be vital for both teams - I think the team that can get the most quality reps from non-starters with their depth will have the best advantage in this slugfest.