After extensively researching this, I replaced the sway bar endlinks and bushings with SPL and Prothane. I still have this (slightly mattress sounding) squeak in my right rear suspension area.

I can still make it squeak by pushing on the rear bumper. My Bilstein PSS coilovers have only 5-6k miles on them. Could it be the rear strut? It doesn't keep bouncing like a bad strut/shock.

What else could it be?

PLEASE HELP!

 

Welcome to the world of performance parts. Your car is modified and will make a few noises over a stock car.

 

Okay?? Not the help I was looking for.

 

Is there silicone lube between the bar and the bushing?

 

Yes, Prothane supplied the lube with their bushings.

 

Isolate the problem.
Try taking off the rear anti-sway bar and endlinks completely (or disconnect the endlinks and ziptie the bar so it does not rattle). Then drive around and see if the noise goes away.

 

You might just want to pick up a tube of white lithium and go to town on the swaybar bushings. Mine made a creeky, rubbing noise when driving over slight imperfections or into the driveway. The amount of lube Progress supplied was not enough. Once properly lubed they were dead silent like stock. Had to take them apart this spring to relube since they began to make noises after the winter storage again. Hope you resolve your issue!

 

Thanks! Somehow it has gotten better. It's still there but not near as noticeable. I'm heading to my shop today, so I'll have them re-lubed.

 

If the problem persists, then it has to be your rear shocks. I had the same problem before.