Best win for either team is BYU over Texas, who Sagarin ranks 25th. Utah's best win is actually over 65th ranked Michigan. Utah's scehdule so far has been very weak, though that will change going forward.
His data isn't a perfect prediction, but probably better than our guesses.
Ergo, BYU would be 4-0 with Utah's schedule so far.
Utah would be 3-1 with BYU's,