After much entertainment, I have completed the engine out -> turbo change -> engine back in job on my S4 - and it mostly went to plan!
Best bit was that it started pretty much first click and, so far, so good with no leaks, bangs or rattles.
However, the oil temp guage on startup whizzes over to max immediately, so I am assuming I've missed an electrical connection (there's plenty of those!) or crimped / broken a wire (hope not!).
Am i right in thinking the sensor is in the front of the block?
VAGCAT seems to say its here, but its not clear and my car is in a mates garage so i cant go looking until later today.
OR, is there something / somewhere else I need to check?
Help appreciated, then perhaps I'll get me old faithful back on the road for next week..!