I took delivery of my 2020 ST in late September 2019. I noticed the suspension noise early, and mentioned it to my dealer, but since I was otherwise generally happy with the ST, I decided to wait for Ford to come out with a TSB to correct the problem. Well time passed, I watched the forum and saw that dealers tried various fixes to no avail, and no TSB appeared. A couple of months ago, I decided to let my dealer take a crack at the problem. Long story short, they replaced both front sway bar links which of course didn’t fix the problem.
I noticed a couple of members post that after they put aftermarket exhausts systems on their STs the noise disappeared. I suspect that the new exhaust system either masked the noise, or the “mellow” sound of the new exhaust distracted the owners’ attention away from the annoying noise. Maybe I should consider a Borla exhaust…………………..