Audi 80 (FWD) rear drum to disc conversion...

[gerard]

just called up an Audi used spares place to see if they might have an Audi 
80 by any chance. Nada. But the guy mentioned the A4 and perhaps using that 
car's rear axle.

Yeah right.

I checked ETKA online. Very, very different indeed after 1991. However, an 
option being an option... would it fit?

It's a loooong shot, but there are more A4 machines than 80s. :P