I don't here it when driving straight over a speed bump instead it's when the wheel is turned to the right it does it almost regardless of bumps while it's turned to the right and over small bumps will make the clunk sound and while it turns back straight coming out of a right turn too more common when at slower speeds making sharp right turns.

 

So I finally decided to tackle this problem. I jacked the car up and inspected all the bushings and ball joints .they all appeared to look good by visual inspection. That's when I dug deeper. With the car off the ground i banged on the upper ball joint at the front of the control arm and when I hit it, it clunked like while I drove over the bumps. I checked the other side to ensure that it was worse than the other side and it was. I bought the individual ball joint for 40 bucks at AutoZone rented their joint puller clamp for 30 and got it done in about 2 hours. Steering feels tighter and I have pictures and videos of before and after if you want as well.

New upper control arm ball joint installed

 

How many miles on your w204
What part of country your at ?
Glad it went well with ball joints
Links to your video would be nice to look at .

 

I'll have to upload them and post later. Mine has 184k miles and is in the states. Oklahoma to be specific.