I have fitted mine but never tested them as the bike is still in full resto mode. But the goal of this design is to eliminate 100% any possible movement of the handle bar, whatever the conditions. The bushings are machined from Delrin and they are as stiff as aluminum. Basically, it is like solid mounting your handlebar. I initially thought I would make them from urethane, but changed my mind as urethane still has some compliance.
Some people will say that solid mounting the handlebar will allow vibrations to reach it. It is possible. But my BMW R1150GSA, which is know to vibrate quite a lot above 5,000rpm, has solid mounted handlebars, and it never bothered me.
I was fed-up with the handlebar getting crooked everytime the bike would drop as well as the lack of precision in twisties. Hopefully the problem is solved now, without introducing too much vibes.