The orange residue you see on the top of the shock tower is the remains of the pulverized upper guide support. It is a dense foam "doughnut" the sits between the support bearing flange (upper strut mount) and the large washer which is under the large nut on top of the shock piston rod.

I had this exact same issue and I first changed the tension strut (the front "control arm") with no change in the noise. I needed new tension arms so anyway so that was my first approach.

After changing the tension struts I ordered the parts to replace everything on the spring strut minus the shock and the actual spring. I reasoned that the shocks seemed to be fine.

I ordered the parts from GETBMW Parts as they were actually cheaper than the nearest competitor by price, BAVAUTO. I ordered the lower & upper spring seat, dust tube, additional shock absorber, upper and lower guide support, spring support flange (The most expensive part at $133), and new nuts and bolts for all fasteners that were loosened or removed. $254 total.

3 hours of my labor but I can probably do the other side in under two. I did one side thus far to track the changes. You'll need to jack up the offending side and then have a second jack to compress the suspension some to remove the spring strut assembly.

You can rent a spring compressor from Autozone or similar place. Spring compressor has to be set one rotation down or directly below the top end of the spring. Place the the other spring compressor 180 degrees from it.
Do not spin the piston rod nut without holding it in place by the hex inside the end of the rod. You can destroy an otherwise reusable shock.

After changing these parts that particular "clunk" sound was gone and the car was much quieter.

Good luck and follow all manufacturers directions on jacking, supporting the car and compressing the springs.