Hi Daniel,
I have a B1600/1800 diff in my Mk2. Tough as nails. Needed to get a Mazda yoke added to my tailshaft and the shaft shortened slightly at the same time.
It's about 15mm wider than a standard escort diff from axle flange to flange, so rear wheel offset and width needs to be considered.
I had the (massive) axle/hub flanges machined down to escort outer diameter and re drilled for 4x108 stud pattern, and also had the centre bore "protrusion" turned down to 63.5mm to suit escort wheels.
I converted to Nissan pintara discs and calipers with their built in handbrake mechanism, and made bolt on brackets to mount these.
Originally I continued to run escort leaf springs with slotted spring seats and larger U bolts to suit the larger size of the diff tube. Later I converted to a 5 link setup.
Petrol diffs seem to be 3.77 ratio or similar, while diesels have 4.44 - great for high revving engines.
That's about all I can think of. Reply or PM if you want to ask anything else.
Cheers
Ash