Knocking of the rear suspension

Hello,
I drive a Golf 3, and I have a 60/40 suspension. The shocks are Bilstein, and the springs are KW! For a very long time, I've been hearing a knocking in the rear axle when I drive through ruts (I probably started hearing it even before the suspension was installed, but it was quieter). The worst is when a fresh asphalt strip comes up, which is too low, so when it goes through with both rear wheels at the same time, you can hear a hollow thud, like something is being worn out! Well, I just wanted to ask if anyone knows about this, and if maybe someone knows where it comes from.
Maybe it's also due to this medieval cross-linked rail system, which is a disgrace!
Hi!

Yes, Bilstein shock absorbers are great, but the KW springs (not coilover suspension!) are much too stiff, and I was told they were comfortable!

Most of the time, the large, embedded rubber pieces are broken. Don't say anything negative about the axle; it's good.