OK. I believe what it happened to be for me, was that my parts (the plastic on them) were brittle due to age/lower quality.

I ordered the same parts again, but with Lemforder (I know, not cheap).

Sway bar, left and right. Balljoints outer (originally Febi, but I ended up replacing with either Lemforder), make sure you also check your control arms bushing "plastic/rubber" for cracking.

The plastic on these parts are what set them apart from one brand to another.

Since you drive a non-m54 truck, this might be slightly different for sway bar.

Please note that on my maintenance (due to 210,000+ km at the time), I also swapped all of my struts and shocks. I recommend Sachs if you have to do this at any time (really nice soft ride).

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2003 X5 3.0i // Winter package
263,000 kM