I have the same problem. I have just replaced the two trust arms, and it got a lot better, but when I drive at 60 mph. I get the shimy. I am about to replace the shock absorb and the tied roads, and I hope this will fix this problem. I know that is quite expencive, but I have to do it.
When is the last time anybody has checked the top mounting nut on the front struts? I was getting the same noise, even when backing up and applying the brakes. clunk noise was even worse when going over bumps. Took off the dust cover, and waaaaaLa. The strut bolt came loose. this solved all the probs, except one. The shimmy at 60 mph