An Auburn is a good diff all around. The major difference is in the way they work and their construction. Auburns are not rebuildable so once they wear out you basically throw them away. They have some sort of conical clutches that are not replacable. A Tracloc, stock diff, has a rebuildable clutch pac. I would rather have a newer style Eaton than an Auburn. Stock is ok but after a few trips to the track on slicks the stock diffs wear really fast.