No bites of the FB groups. I've found there are certainly less Audi's here in TX, and less mechanics to go with. The climate really doesn't have much need for Quattro, and with all the dry weather it makes RWD high HP cars even easier to own.
Anyhow, I used this Google search term and looks like there are a few Houston shops (houston tx audi euro mechanic). Give a call and see how they sound.
Again, you could call Mike at Brink Motorsports in Austin and ask him for a recommendation, but I'd feel a bit guilty myself as I'm sure he'd like the business. I can confirm Brink is a solid shop with some good mechanics who treated my car right.