Shaking/Shimmy w/Highway Driving

[Easywin]

While driving on the highway (and at slow speed to a lesser extent), the steering wheel shakes left to right. I have had the tires balanced twice since I got new tires. While changing the oil I decided to check the tie-rod ends and swaybar linkage. All of them are loose on all four corners. Is this normal?

I don't think the problem is in the struts, because I don't notice an excess of bouncing while going over bumps. I did check the boots for the CV joints and all is well there. The car does have 140K miles so anything is possible.

I have found a shop, that supposedly will tell me what is "wrong" and let me try and fix it myself, should I take it there and see if they can diagnose it for me?

On a semi-unreladed note: Are there warning signs before the CV joints start clunking? While checking the tie-rods and swaybar ends, I tried turning one side of the CV, similar to checking the wear on a U-joint, and everything was tight.