I have the rare 06' 2500 4x4 that came through with an open rear diff. Looking into fixing that, I see the stock helical gear LS from AAM on ebay for about $550, and the detroit truetrac helicals for about $750 . Is the detroit worth another $200? I have heard that the torque bias is 4:1 on the detroit vs. 2:1 on the stocker, but I can't verify what the bias is on either of them.