He's using a Chevy auto, no doubt with a custom driveshaft (probably one-piece). I'd say the diff should be able to handle it, I don't think Vorschlag changed theirs.
Iron block chevy v8 is going to be way heavier than an M54. M54s are lighter than the e36 24vs, too, so....probably a substantial weight gain there. Still waiting on additional pictures where the car will actually work and retains a/c, ps, etc. as stated in the first post.