I used Febi to replace left and right front door handle carriers in my '01 back in February.
51-21-8-243-615 front left door handle carrier
51-21-8-243-616 front right door handle carrier

I got them at RMEuropean, with free shipping (ground, but actually always comes overnight to California) for about $40 each.

Visually, they looked just as high quality as the OE ones, repeating the OE design flaws to perfection.

Some on this list report fitment difficulties with the Febi. But I had no problems. I even found one area where I can see if a certain part was not tucked in right in the right sequence, it might cause problems.

Others on this list report swapping cable assemblies from the OE one to the new Febi. I did not do that, but saved the old ones, just in case.

But I did everything myself, and would do any repair myself. I know the decision making might change when you're paying someone else to fix it.

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2001 X5 3.0i, 203k miles, AT, owned since 2014