1995 C220 - Obnoxious Squeeking Noise from suspension

My car has been making a loud squeaking noise from the rear passenger side tire/wheel area. It has gotten progressively worse over the past several months to the point that it has become not only embarrassing to drive around anywhere but also terribly annoying. More often than not, I have to turn on the radio just to block out the noise inside the car.

Last fall, I took the car to the dealership (when the noise wasn't so loud) and specifically asked them to check the suspension to determine the cause of the squeak. They were unable to find anything; however, they did replace the rear flex disc. However, that did not eliminate the squeak. Earlier this year, after showing the car to several different mechanics, the consensus was that the source of the problem was the rear control arm and the connecting rods. Each mechanic concluded that the shocks were fine and not the problem. Hence, I had the rear control arm and the rods replaced on the passenger side. The noise disappeared for a week or two but then returned again with the same loudness. This was also the case when they replaced the rear flex disc. In May, I took the car to another dealership for a 30K service and again, asked them to specifically check the noise along with the flex disc in the front (because now I was beginning to hear a muffled noise from the front suspension, but not at all similar to the one in the rear). They told me that the front flex disc was fine and that I need to change all four shocks as they were the cause of the squeak. Unable to come up with another solution, I had all four shocks replaced in hopes that the problem would finally be fixed. Given that the car has 165K miles on it and still had the original shocks, I think it was ot a bad idea to replace the shocks regardless of the noise issue. However, replacing the shocks hasn't solved the problem either. The squeek is still around. I am quite concerned about this horrible squeaking noise and was hoping that the members of this forum may be able to shed some more light on this dilemma of mine.

One last thing. Someone else had mentioned a this in an earlier post; when reversing out of my parking space in the morning, I hear a muffled popping sound from the front of the car. It just happens once and almost routinely each morning. What could the cause of this and is this something that may turn into another nightmare for me?

Any help/comments would be greatly appreciated. Thanks a million.