I found the source of my squeak, but forgot to come back here and post what I found.
Please bear in mind that this applies to my situation. You may have something similar, or it may be the brakes as indicated above.
I installed Hotchkis Sways. The squeak on my C was coming from the front sway bushings. I had lubed them on install per instructions, but I guess with the roads, my driving style

, and the tight bushings, the lube all squeezed out.
I've dropped the bar twice now to re-lube. I also had a conversation with the guys at Hotchkis to see if I did something wrong. The did suggest that I use some premium suspension lube that I have yet to pick up.
HTH
Happy New Year!
jimt