I'd say it's the same part. Look at this:
http://www.hpieurope.com/piw.php?lang=en&partNo=hbc8019
Stock cross shafts fit fine and are ample strong, you may need to sand a few thousands off the length to get them to slide in easily. Don't take off any material until you do a test fit.
As far as the diff oil, the thicker you go, the quicker things will ware down inside . . . IMO. I'm using grease now; added benefit is no more leaks. The diff oil always seems to squeeze past the o rings and get all over the bearings, even with the green slime and new rings. Just been my experience.