Looks like Claude replied to me instead of the group:
Hello Florian,
I have a 1997 OBW with a similar problem a few years ago. It was the bushings of the cross bars attached to the torsion bar that were worned
out. They changed the two links and it fixed my problem. Check also the bushing of the torsion bar itself.
Before attempting to pay for new cross bar linked to the torsion bar, Check if it would be possible to changed just the bushings of the cross bars.
It would be a lot cheaper than to pay 64$ CAN + 15% tax each like I did..
Good luck.
Claude