We hit on the East earlier today; now we move on to the South Regional. As we promised in the Giant Killers blog, today we begin detailed breakdowns of all the first-round games with GK implications. In case you've forgotten, a Giant Killer is a team that beats an opponent seeded at least five spots better and doesn't come from a BCS conference. Other teams -- Gonzaga, Butler, BYU, Xavier, Northern Iowa and Temple -- are excluded, too. Check out our methodology for a full explanation. Our model generates statistical ratings that compare potential Giant Killers to past Davids as well as all Giants to the Goliaths who were slain. Those ratings enable us to predict the chances of an upset in each matchup -- and this year looks like a doozy. In the South, no team qualifies for "Best Bet" status, but there are four teams bidding for upsets worthy of deep analysis (and two Giants who look totally safe).