I'd like to bump this, as I'm looking into it myself as well. from a viscosity-protection standpoint, it sounds very good to use, but doesn't seem recommended for clutch type diffs, which is disappointing. I'm actually OK if they diff's clutch packs DONT grab as well, as my rear diff is extremely aggressive, and mine BANGs as it is anyway from time to time.
Could be friction modifiers. So I guess the question for me is more, will this Lightweight shockproof protect my rear diff (Cusco 1.5 way rear diff in Evo) in autox & road racing, and some street?