Hi Eugene
I would be very interested to know hoe you get on, I have the same problem, a very violent steering shake when going over 50 or hitting a bump.
I have changed all bushes,damper,springs,shocks,bearings, and the only thing left are the swivel bearings and shims, although I cannot feel any real movement when jacked up.
please let me know how you get on, as I am getting near to the point of depair.
Steve