[BiturboS4] timing belt interval (from Audi)

[DAK]

I've talked with Audi about the service interval (on my 2.7T A6). The
owner's manual states 104K miles. Audi first said 90K on the phone. When
I mentioned some people had earlier failures (54K in one case), the rep
said, then we recommend 60K... So, what to make of this?
A few questions to the list;
1. Can people send me details of actual failures at <100K miles?
2. Has anyone had the regular timingbelt/waterpump, etc. service done?
Where, How much $?
3. Has anyone priced out the parts for a DIY job? I've done the belts on
2 different 5cyl turbos... thinks look a little different on this
engine! :-)

Thanks!

David

PS. I'd like to add a Biturbo S4 as my commuter car once the A6 biturbo
6-speed is paid off...