I just noticed, while rotating tires/checking brakes etc. That when the steering wheel is turned all the way left, the sway bar link mount on the strut makes contact with the front left brake line, producing a "click" sound. Mayhaps, this is the elusive clunking in steering problem?

 

I believe that the HHR's sway bar set up, and some other cars as well, leads itself to have some clunks or just be less smooth than other cars. A sway bar limits suspension travel and takes away some of the independence of an "independent suspension" as it ties both sides of the car together. The HHR doesn't seem to have a lot of front suspension travel and experience with other cars with limited travel usually means a some "roughness" in the suspension and steering systems.

Here is my first hand experience with what I did on the HHR. When I bought it, the sway bar bushings and links were original-5 yrs old, 50,000 miles. I literally pulled the links off the car with my bare hands and minimal effort. As I didn't have the money to buy new links, I drove around without the sway bar connected for 2 months. I noticed some more body lean in tight turns but that was it. The suspension was quiet and the ride was better. Now, the sway bar is totally off the vehicle and the struts are brand new in the front and the car rides and handles quietly and nicely. I have a small rattle type noise in the steering column occasionally but that noise is indicative on many GM cars and trucks and replacing the column or intermediate shaft will only temporarily make it go away, it's just the normal slack in the steering column that makes it collapse in a crash and GM hasn't been able to fix it for years.