Its really not too bad a job for a competent home mechanic,pull off front bumper and put in service position, remove aux belt and tensioner, remove top cam cover, remove bottom pulley and bottom cover. I got all my parts from TPS when they had an extra 10% off cambelt kits, (i have a trade account), just set cylinder 1 to TDC and check mark on cam is aligned, i put my own marks on the bottom pulley before i take old belt off, no need to guess the tension as it's done automatically with an oil filled damper. Put on new roller tensioner and replace the damper if its done over 120K or looks like its leaking oil.
When i did the belt and damper on my 1.8T B5, the tensioning idler roller was missing and the belt had been rubbing on the lug on the damper body for over 70K miles, the belt had been done when i bought the car in 2003 by a so called Audi specialist! I like to do as much as i possibly can as i believe i can do a better job than most garages, i like to take my time and clean everything, copper slip screws/bolts, torque and loctite screws etc. It may take me 6 hours, but its a good feeling afterwards.