Well,
After a lot of research, heart-ache, purchase of two incorrectly identified diffs and two months of concentrated searching, out of frustration I've finally dropped the dough on a Quaife assembly for my 12mm 3.9 R200.
It was $1,299.00 + $15 S&H delivered from Bildon Motorsport in PA. Although they specialize in VW's they carry the full line of Quaife assemblies.
http://www.bildon.com/catalog/drivetrain/
This was the cheapest place I could find. Virtually everyone else was selling them at full retail $1495, so the $200 I saved will pay for the rebuild/refresh on my R200.
This should handle anything I can throw at it.
Even though I've blown the budget straight to hell, after reading all the reviews, suggestions and desires from the forums of everyone that wanted a Quaife but had to settle for the clutch LSD due to financial constraints, it convinced me that since I'm FINALLY in a place in my life where I actually DO have the money, it was worth it. Does it increase the value of the car by $1500? I doubt it, but it's an enthusiasts ride for enthusiasts!
And I'm comfortable that I can use this without fear of breaking it or wearing out clutch disks (not likely I know) but the psychology is as important as the reality!
Cheers,
WW