1995 Cutlass Supreme rear end noise
 

This car developed a rear end noise going over every little bump which sounded like the rear struts needed to be replaced. After her mechanic installed new Napa Response struts the car makes the same awful noise. This guy is a construction mechanic, dirt track car racer and is a good friend of the hens for years. He told her when she replaces the front struts the noise will go away. I am skeptical about this explanation. The hen says she is pretty sure he did not test drive it after installing the new struts. What does anyone else think about this?

Were the strut mounts checked/replaced? Other than that, possibly sway bar links if you can crawl under it and have someone bounce it, you should be able to hear/feel it, grab the link on the side that's making noise if you feel the clunk, that's it.

It doesn't sound like a clunk but more of a squeaky door. He did say he greased up the mounts but did not replace them. Could this be the problem?

Could be also could be a sway bar bushing, or any other bushing under there. If you can narrow it down and spray it with some WD-40, it may take care of it, at least temporarily.