Audi recommendation wanted

[Andreas Meyer <meyer@hpanix.an.hp.com>]

Ok, I am in the market for an Audi for my wife. The only
problem is that she refuses to drive with a stick and
insists on a slushbox. The model and years that I am 
thinking of are the 89, 90, and 91 Audi 100. I know that
in 91 Audi went to the 4 speed automatic and in 89, 90
they used the 3 speed. The question I have is how reliable
are those trannies. I looked through the archive and saw
some of the same horror stories that I heard of before,
i.e. Audi slushboxes don't seem to last very long and are
VERY expensive to fix. There was one person who wrote that
it cost $5000 to replace the tranny (covered by warranty).
Stories like that certainly make me think twice about 
that car and tranny combination. What experiences do other
people out there have and how much can I expect to spend
on having the tranny rebuilt in case it does go south?
Also which one is better, more reliable, cheaper to fix:
the 3 speed or the 4 speed?

Thanks for any info you may be able to provide,

Andreas Meyer
former Audi 5000 CSQT owner and wannabe again