857525053 KTS 2 rear differential

[Adam_cambridge]

Hello, please could someone help me to find out anything at all about the Audi rear end that I have just bought. 

I am particularly interested in finding out about the rear diff; the casing part number is above along with the code KTS. 

The previous owner told me that it was removed from a 1984 Audi 80 quattro but had no other information. 

Google searches revealed a "KTS" rear diff for sale from an Audi 100 but the photos look nothing like my diff. My one looks like the 1980s b2 rear diff from the Audi 80/90. 

I can't find anything useful on ETKA.

Ideally I need to find the ratio and the original vehicle as I'm planning to use the whole setup in a 4wd conversion using an 01E quattro box.

Many thanks in advance.