Does anyone know whereI can get step-by-step instructions for replacing rear rotors and pads? Is there a special tool needed to reset or compress the calipar piston? My car is 1999A6 2.8. Thanks.

Do a search of Stoney's Links at the following link: http://sonolithics.com/files/a6_links.html
There you should find answers to alomst all your questions.
I bought a universal caliper press thing from the local Harbor Freight Tool for like 40 bucks.

Jeff

you can do the loaner tool program at your local autozone. you pay like $35 dollars for it and when you return it you get all your money back. DO NOT use the cubed tool. it sucks. hope this helps.