It worked for me too. After I changed to RedLine High Temp ATF, I had a binding in sharp turns.

Subaru advised me to add Goodwrench LSD friction modifier, and it cured the problem. GM part number 1052358.

Redline sells such a modifier also. See at:
http://www.redlineoil.com/products.htm

They add it to their diff fluids, but not their ATF, apparently.

~John