Mark Barron won't make it into the 20's either but that mock is a pretty good gauge how things could fall. Would hate to be so close to Kuechly and not get him over Hightower though. That would hurt.
If you read up on Kuechly at cbssports.com you will find a good amount of negatives on him that could make him fall in the draft. These negatives almost make me hesitate in taking him at all.
http://www.cbssports.com/nfl/draft/players/1664814