I have a 2.8. I'm not 100% on the intervals for changing the cambelt, but mine was also done at 80k at the dealers. It has now done 130k and I have just had it changed again, only so I do not have to worry about it! Time is a factor too. I'm pretty sure Audi reccomend it changed every 5 years regardless of mileage due to exposure/weathering. if you can check (if in doubt phone the dealers where the belt was changed and they will have everything that was done at the sametime on record) if the waterpump,thermostat,pulleys and tensioners were changed at the same time as the belt. If they were not (meaning the previous owner was a tightarse!) then I would get everything done as a precaution. AdamS24 changed mine along with everything else that should be changed with it. His prices are EXCELLENT and I highly reccomend getting in touch (he is on here) if you are not doing the job yourself.....
Ollie