The standard diff is mounted in such a way that is a part of the cosworth subframe, hence, the acting forces are taken up in the beam. The rear support is designed mostly for vertical loads - hence the sloppy oem hanger.

Using the adapter kit, all these forces are forced through the rear cover and into the hanger, which is NOT designed to handle the torque.

The front brackets are not supported well enough through thin plates. The casing on the OEM diff is stiffening up the whole beam in this area, transfering the loads into the beam and beam mounts. The adapter brackets will inevitably twist.

Originally, the diffs are held in place in 4 places on the rear cover and two at the front, preventing front to back rotation, and as axial (to the pinion) torque.

The design is simply not good from an engineers point of view.

My reason for getting the kit is that it locates the diff correctly, so I will use it as a jig to modify my beam for the front pickups, and create a diff hanger similar to that of the 9" diffs, only larger to accomodate the lower mounting points as well.