Thanks to Ridge, he has spelled out everything needed with
a reply to "slipping trans and a long way from home" which
is currently on page 4. There is another related thread at
the top of page 3. Of course you still could use a donor car
but many of the how to's have been covered.
Alternatively, you could save your bucks for a manual trans
car such as the 240d or Euro 300d, neither came with a turbo
but that is something I can live without.
(won't be missed in stop and go traffic)