I thought I remember reading that the 1st and possibly second gen diffs from Intense didn't pre-load but the 3rd gen did.
EDIT-
http://www.intense-racing.com/gen3lsd/gen3.html
"Our original intention with the Third Gen design was to retain a preloader design similar to the one in our Second Gen LSD. But in analyzing the failures over the last year, we were able to engineer a completely different approach that has proven superior to the current design. It is now physically impossible for the preloader to shift or ‘walk’ out of place, which has led to cases of differential destruction in the past."