[DarkSammy]

All UE Spider 6 or 8 diffs are just OFNA diffs with his own cups installed, and your cups are all UE. They are excellent wearing and very good quality. That being said, the spider 6 diffs UE sold are an old design, you may just have some kind of newer version OFNA case with the same internals.

The bevel gear looks to me to be helical cut, which are renowned to feel a lot rougher than other types of gears. I cant tell from the pic all that well, but it does look like that is the case. I am told the CEN diffs which are helical cut are amazing in terms of heavy duty, so you might find they run awesome for you. So long as you shim them well, they should serve you well. :)

Keep the updates comin...