the figure 8 is supposed to break in the clutches on the AWD section.
maybe this thread will help:
http://www.subaru-svx.net/forum/showthread.php?t=23074
Do a search using some terms like figure or binding, etc and read a few and see if anything seems like it will help is about all I can say. Its just my opinion, but putting in LSD additive is a cover-up of a problem and cover-ups are not generally a good thing for longevity.