It's going to be a heck of a game regardless. I am sure Indy has been studying the film of when New England beat the Bears this year, and if any QB could duplicate what Brady did, it's Peyton Manning. If Peyton and the offensive line can figure out how to successfully deal with the stifiling Bears defense, Indy has a very good chance to win.
That said, I think the key to the game is which Rex Grossman shows up for the game today. Yes, Indy's defense improved over the last few games, but it is still lousy. If the offensively inept Grossman shows up, Indy's defense might be able to keep up. If Grossman is on his game, I don't think the Indy defense has a chance.
These teams are such polar opposites, anything could happen. If the Bears can shut down the Indy high powered offense, even if the inept Grossman shows up, I think the Bears would win. If the Bears defense can't stop Indy, then the Bears better hope that Grossman is on his game because that's the only way they'll have a chance of keeping up with Indy.
Personally, I'm rooting for the Colts. Peyton, IMHO, is long overdue a championship. Also, I'm still not over the desicration (sp?) of my Patriots by the Bears in the '85/'86 Super Bowl.
Regardless, t'will be a fun game to watch, if it doesn't get rained out.