Don't forget that the CPO vehicle from Audi already includes a 1 year extended warranty with unlimited mileage. And you are technically paying for that via purchase. You should see it in the paperwork, not a bad thing, just a heads up.
www.audiusa.com
I'm sure the dealer will offer an extended warranty as well, either via Audi or 3rd party.
If I'm considering one, I'll start by researching whatever they are offering first. Especially since I'm most likely to bring the vehicle to them for future service visits. I also like to get feedback from the service department.
I passed on the extended warranty for this vehicle because they were way too expensive and surprisingly, they didn't even bother offering a discount. Although even at half-off, I wasn't touching it, so I didn't push it. Plus, for my personal vehicles, I don't typically keep them long enough to be of use.
Which is worth noting that those warranty prices are almost always negotiable. Just be sure to read the fine print and note deductibles and whether it's an inclusion or exclusion based warranty. It does no good if it excludes half the vehicle or only includes things that probably won't break.