According to Phil Steele- a pretty objective and accurate assessor of talent, this is how he ranks BYU vs. their opponents- by position group:
BYU Advantages:
• QB-
BYU: 18
Utah: 42
Advantage BYU ↑ 24 spots
• OL-
BYU: 47
Utah: Not Ranked
Advantage BYU
UTAH Advantages:
• RB-
BYU- Not Ranked
Utah- 16
Advantage Utah
• WR-
BYU- 59
Utah- 48
Advantage Utah ↑11 spots
• DL-
BYU- 35
Utah- #1 in CFB!
Advantage Utah ↑ 34 spots
(Where did you get your info?)
• LB-
BYU- 47
Utah- 19
Advantage Utah ↑ 28 spots
• DB-
BYU- 23
Utah- 12
Advantage Utah ↑ 11 spots
• Special Teams-
BYU- 43
Utah- 23
Advantage Utah ↑ 20 spots
You're right- according to Steele, Utah is the #8 best team in America. BYU- #38. If both teams play their best, Utah should win, easily. (Other CFB magazines, experts, and polls also show that Utah is better, and more talented, with more depth.) This isn't really refutable, among objective experts.
The only question is will Utah play their best, or will they play sloppy, with multiple turnovers, and failed red-zone trips, as they have in the past 3-4 years.