I don't know how reliable or respected it is, LOL. It is virtually the only one, however.
When you jack them up about errors, their customer support is nil and the phone beaver just parrots the company line that they just publish the information given to them by Audi.
As for Audi, fageddaboudit. They have zero interest in correcting any of their data.
And your point is??
All manuals are a guide, apply common sense with use and yes the manufacturer (Audi in this case) has zero interest in after market manuals or their accuracy. Bentley is much better than Clymers and Haynes.
Pricing posted is less than others advertized including Amazon and they throw you shipping, seems fair for a guide.
I am in since it does not appear that you can buy a factory manual with service updates like you can with the P car, although the same parent company.
As you see new to the list and a C5, thought I would try this Forum for a while to see if there is any constructive exchange of information and passion of cars.