I don't have any links. Quaife only offers 1 LSD to the public and it is already in our transmissions, AFAIK. I had heard rumors that the LSD that they sold seperately is better than the one GM put into our cars, and that's only because GM didn't want to put the top of the line part in there. But I cannot confirm that... so it is just a rumor.
But I do know of "someone" that has a transmission with a Hi-Helix Quaife LSD in it. Actually, IIRC, its the only Hi-Helix Quaife LSD in the world. Haha, so that one doesn't really count.
There are other brands out there though, if I remember correctly. Been a long time since I looked into it all.