Is there a belt change DIY somewhere ?
 

Hi. want to change the two belts. I can see the tensioner bolt for the main belt, but how do you remove the supercharger belt. Things a very tight in there.

ok, got the supercharger belt off and partially removed the main belt. but the main belt doesn't look like it can be removed without removing the supercharger belt idler pulley. is that true?

https://www.audiworld.com/forums/a6-...ement-2886198/ covers removing the supercharger belt. Did you manage to get the accessory belt off without removing the radiator?

Do not remove the radiator. To remove the inner belt, the supercharger idler pulley needs to be backed off (but do not remove completely). To do this you will need a low profile torx set used in conjunction with a standard fan belt bar (tool in fan belt kits) to break loose. Once broken loose use your fingers to continue to loosen until it is backed off enough to slide old belt out and new belt in. Even with the fan belt bar and low profile torx bit there is no extra room.
I put the front of the car on ramps and did removed the noise insulation cover underneath. I changed both belts for the first time at 100K miles....both belts look like they could have lasted another 100K miles based on their condition.