TCU's defensive line weights by starers are 275, 320, 285 and the backups are 295, 315, 290.
Montana's defensive line weights went: 265, 285, 265 and backups are 245, 290, 245.
That stood out to me, TCU's D-line was effectively bigger across the board. All three had good size, mobility, and skill there. Montana would have needed to close Gub and Alford twice to match that type of D-line and still wouldn't have a 300+ pound nose. Not that I expect UM to amass that much size on the D-line, but it did stand out to me that TCU's DL was pretty big as a whole unit, not just in the middle.
3 of TCU"s safety / NB crew were over 6-2 and 200 pounds - so they had another guy that added a combination of size/speed in the slot.
#57, their O'Connell equivalent (I think) had incredible range and about 10-15 more pounds that Patty was reported at.
TCU, being who they are, can recruit and build their defense differently with bigger/faster guys and thus it makes the defense work a little better. I went back and pulled their stats in the B12 and it was really middle of the road overall - neither their total/rush/passing defensive stats stood out, ranked 5th or 6th best. But what they were tops in defensively were sacks, interceptions, and defensive TDs. It appears that (when working) their defense is designed more to be disruptive than overall dominant.