I myself have tried asking this question before, but everybody seems mum and can't give a straight answer.

What I've seen so far is that the 450 has a different flywheel mated to the crankshaft that would not work with the 560 tranny. Thus in order to do a swap, you'd have to replace the flywheel AND crankshaft which is a pain even to think about.

Now, what about the Porsche 928 S4 tranny's? I understand these engines were derived from the Mercedes 4.5 and 5.0 litre's , so interchangeability might be an idea?