OK, I ordered the HB diff and it came in today. It is not the same as the sportwerks/muggy diff. The diff case is almost 1/4" longer than mine, and will not fit my setup at all.
Well, actually, I ordered everything I needed to build the diff, plus the Kyosho spurs. it came out cheaper than getting the whole diff. Now, I don't need any of this stuff. Any takers, I'll make you a deal.