I bought some last week after reading about it on another thread and can confirm it make the forks more active on small bumps etc.
Silicon spray will do the same and I believe that is what this stuff is but who knows.
I’ve had it on a ride once or twice and seem to depend on conditions i.e. wet muddy rides with steep descents tend to bring it on.
Always fine in the dry though.
No nasty dremel work required just about 5 seconds to remove some poor machining burrs.
The turner forums on mtbr recommend the deep cup lower to reduce stress on the headtube.
Well worth the 5 seconds it takes IMHO .
Not the prettiest of headsets but just fitted to my 2011 5 spot.
Had to dremel a slight lip off the inside of the headtube due to the depth of the lower cup.