Illinois is ranked 20th in the Country with an Adj EPA/Play of 0.14. The next best offense we played this year is Purdue at 42nd with only 0.06 (and we saw what they did to us). After that you go down all the way to 60 to find Oregon.
Our defense is a lot better than it was when we played Purdue but we'll definitely be tested.
Their defense on the other hand is ranked 121st, allowing 0.12 adjusted points per play. However, they fired their DC after Game 4 and think they're a lot better since then.