I agree that GT and the offense worries me a bit. I love Paul Johnson, and was one that was "Begging" for him to come to NU...... (but I am glad we have Bo)...........and the fact is, the option game works very well in the middle of the season because teams only get 1 week to prepare for something they do not see........ one must remember, that NU would get 1 MONTH , with one of the BEST defensive minds in football, to prepare for this offense. With this in mind, I don't think you would see the "undiscipline" that you normally see from a regular season opponent. Just look at NU's bowl record in the 80's......when team's had the time to actually prepare for the option, we were very ineffective. It wan't until we were loaded with NFL quality players in the 90's that we were able to roll. "Jimmy's and Joes....more than X's - O's"
I would venture to guess that GT hasn't seen offenses similar to the potency of the Big 12 week in and week out either.
Remember, I think GT would be a problem for NU, but I don't expect a "blow-out" like you may be predicting.