I usually tend to stay away from Northwestern games because they're never good enough to win when they're expected to, yet they always are plucky when they're expected to get blasted. Of course this year's team is different.
But, if I had to wager, I would take Minnesota with the points. MN-NW games are usually close, down to the wire games. The last 8 games between the two, 6 of them have been one possession games ('09, which Decker scored late to make it a two possession game, and '11, Kill's first year, are the exceptions). 3 of the 6 were 7 points (8 in '02), where the winning TD was a late play ('08 NW's INT return late & last year's Myrick kick return).
These two play tight, exciting games. I don't expect anything different this Saturday. I think a 3-4 point victory either way won't be a shock.