The model 012 transaxle was available on everything Audi (except TT) 5 speed 2WD from about '97. There was an 013 and 089 model crossover ending that year. Some A8's had a very low ratio 1st gear (I think they were the US models). Others' however, were quite good. Certain codes of the 012 from Audi A4, A6, had the following *net* ratio's (gear x diff): 12.95, 7.18 4.81, 3.48, 2.92 In comparison, the Audi 016 5N: 14.80, 8.75, 5.59, 3.99, 3.00 or the Audi 015 AZZ: 14.00, 8.29, 5.68, 4.16, 3.35. (And) Just for fun, here's the Corvette Z06 (6 speed) model MM6: 9.09, 6.09, 4.45, 3.42, 2.53, 1.71, and the Porsche 930 (4 speed) 9.49, 5.49, 3.76, 2.66.
I have personally held the KEP 016 master tooling plate up to my 01E 6 speed. Only three of the bolt holes line up, and the starter pocket is rotated very slightly clockwise. Now, since the 01E and 012 were available on the same Audi motors, I speculate that the bellhousing patterns are the same. Using that logic, I suspect the 01E adapter plate (like the one offered by RF) would likely work on the 012. Quaife does offer an LSD for the model 012. This is not an endorsement of the 012's strength; simply information.
Cheers,
Andy