I would think all of these system would make the car extremely nose heavy. If I recall, the engine sits in front of the front differential on a Subie. They can do this because the engine is so short. On an Audi, the differential is close to the same as a Subie but the differential is part of the
oil pan.
I would think you would need something where the front differential assembly is independent of the engine. This way, you can move the engine toward the back a bit to get closer to a 50/50 weight bias.