Audi 4000 fuel level sending unit

[Ti Kan]

My Audi 4000's fuel gauge isn't reading properly, so I think I need to
replace the sending unit. The part number is 811919051B but it is NLA from
Audi, and it's not on Audi Tradition. I found that it cross-references
to VDO 221-824-022-006Z. Any tips on how/where to get one?

Thanks,

-Ti