[suicideneil]

This thread has all the info you need in the first couple pages.

The hyper diffs are no different to the HB diffs with regards how you swap the shafts, fill the diff cups & shim the pinion gear to set the mesh correctly. Only extra thing you might need to do is use shims on either side of the diff cup to remove any side to side play that is noticeable ( in the output shafts ) once the Hybrid bulks are assembled- I didn't need to personally. Just pretend the Hybrid bulks are the UE diff case, and then the principle is identical.

Oil weight is personal choice to suit your driving style, but generally guys seem to go for 7k front & 5k rear ( I did, pretty generic setup ), 7k / 3k, or 5k / 3k- I'm don't have a great deal of advice to give on what will be the best choices for any given surface or driving style, shock & diff tuning has never been my strong point; talk to some truggy and buggy racers though and they should be able to offer some helpful pointers.