There is more somewhere, but, like many things it is probably hidden in some three page thread with a topic that has nothing to with transaxles.
The 944 has a much more favorable ring gear and is a good candidate to swap into the Audi unit, they fit fine. A nice combo is the 5N Audi box with a 3.44 ring gear from the 944 box.
The 944 has different indivdual gear ratios too, but the gears are welded onto the shafts and cannot be swapped.
Ron