There's no question that it's certainly early on in the process but I always do initial power ratings on teams in January. I update them after Signing Day, update them throughout and after spring practice and then constantly tweak them in the Summer.
For example, here's how I came up with my Florida and Michigan power rating. First my final power rating on Michigan was 89.95. I downgraded them 3 points because of all the attrition they are going to suffer especially on the defensive side of the ball. I didn't downgrade them any further because they were already pretty low in my power ratings from losing 3 of their last 4 games and Harbaugh has done a solid job of recruiting the last 2 years. So my January power rating for Michigan is 86.95 which will get adjusted multiple times before the season starts.
As for Florida, their final power rating was 84.93. They got a boost due to their big win over Iowa in the bowl but again their power rating was already down because of their blowout losses to Florida St and Alabama at the end of the regular season. I downgraded them 2 additional points because of their heavy losses on defense (possibly 5-6 players taken in the first 3 rounds of the draft) but I do expect the offense to take a step forward no matter who is behind center. So my January power rating for Florida is 82.93 which again will get adjusted multiple times before the season starts.
Then you factor that this game is being played in Arlington, TX which is completely neutral for both programs and fan bases. Therefore, it's a simple formula in that you take Michigan's power rating of 86.95 and subtract Florida's 82.93 and I get Michigan being favored by about 4 points here.
Hope this helps.