For what little it might be worth, we score 84.6 PPG and give up 73.4 PPG. Iowa State scores 75.5 PPG and gives up 61.2 PPG. These are the offenses we have played that are better than Iowa State according to KenPom and the points we allowed against them (ranking is their overall offense ranking nationally). For reference, Iowa State's offense is #49 nationally, and we are obviously #1. In reverse chronological order:
87 vs. #18 Wisconsin (Minneapolis, MN - BTT)
87 vs. #32 Nebraska (Minneapolis, MN - BTT)
74 vs. #40 Ohio State (Minneapolis, MN - BTT)
61 at #15 Iowa
77 vs. #3 Purdue
83 at #18 Wisconsin
85 vs. #15 Iowa
84 vs. #32 Nebraska in OT
75 at #40 Ohio State
96 at #36 Northwestern in OT
83 at #3 Purdue (no TSJ)
66 vs. #36 Northwestern (no TSJ)
86 at #29 Tennessee
89 vs. #22 FAU (New York, NY)
71 vs. #19 Marquette
So, from the standpoint of OUR defense, it is a bit of a mixed bag. All in all, we held a better offense to at or below ISU's average PPG in 5 of those contests. We will certainly need one of our better defensive efforts, but I do NOT think Iowa State will beat us by scoring in the low 70s ... JMO.
Since Iowa State is the #1 defense, there really is no "better" comparison. However, this is how many points we scored against top 25 defenses this year, again in reverse chronological order:
85 at #12 Maryland
80 at #11 Michigan State
86 vs. #4 Rutgers
67 vs. #12 Maryland (no TSJ)
71 vs. #11 Michigan State (no TSJ)
76 at #4 Rutgers
79 at #3 Tennessee
64 vs. #18 Marquette
Conversely, we have scored significantly more than ISU's average points allowed per game in all of our matchups against top defenses.
TL;DR
This KIND of says what we already know ... Iowa State's defense will be good, our offense will be good and it is likely the team that has a "better than usual" performance in their weaker area that wins the game. However, I will PERSONALLY take the bet that the elite Illini offense is less affected by the elite Iowa State defense than the other way around ... so if our defensive effort is there, I like our chances.