the GPR is sweet as far as the hardware goes, but it is so dang stiff on the initial sweep...all three of them have been that way. Once you get riding, it goes away, but you can still feel it compared w/ a Scotts or non-damper bike. It handles the high speed and low speed jerks fine. As far as headshake, get your bike to handle w/out headshake first...the stabilizer isn't for curing headshake. It is for keeping the front end planted on high speed runs and low speed trail junk (which allows the fork to take the blow instead of deflecting).
As far as the bar height w/ the Scotts, I had heard that too, that is why I'm still running a GPR on my KTM. It raised my bars about 3/4", which actually felt pretty good. On my CR it was gonna raise it almost 1 3/4", so I stuck w/ the 1.0.
I jusut wish the GPR had more adjustability.