I had a 1993 9000 CSE auto and got panicky after hearing tales of auto
transmission failure at around 120K miles. The box showed no symptoms of
failure, and the car kept going well until I sold it with well over 120K
miles on the clock over 6 years ago. I saw it still on the road only a
couple of days ago funnily enough. Whether it still has the same 'box is
another matter, but I suspect that replacing the box on a vehicle that age
('93) might not make economic sense.
After I'd sold it I was talking to the service manager at my local dealer,
and in his experience most of the 120K failures tended to be on the FPT
models - particularly if they have been driven hard. My car was an ordinary
2-litre injection model (very underpowered in auto form), and in his opinion
the life of the box may be well in excess of 120K if it's maintained
properly.
The service history of the car and what sort of life it has had must also
come into play with the auto box. Skipped fluid changes, lumps of muck
floating around in the system, and copious use of the loud pedal all
contribute to wear in the box of course.
I'm not sure whether this helps, or serves to add to the dilemma!