Sorry, I've been off the forums for a while. But everything you heard is true. You may be able to get more out of your timing belt than 100k miles but why risk it? Usually, it's the tensioners or the water pump bearings that go out before the actual belt. That stuff you can't see. So yes, you need to change the water pump, tensioners, rollers, valve cover gaskets and all. It's usually a $1200 job. If you have a personal mechanic, you can find kits with (almost) everything you need for around $400-$500. You should check out places like ecstuning.com & blauparts.com to see what the kits consist of. The car will last if you just do the regular maintenance and keep the fluids replaced.
By the way, I'm the 2nd owner of my 03 A4. I bought it with 118k on the clock and it came with all the service records from the dealer. It only had full synthetic every 10k miles and I continued that schedule.