Sign up on lonestarstangs.com there are a lot of ppl. there that can answer you better. In San Antonio, you can get a very good tune from Mike Murilllo at Murillo Motorsports. I've also heard good things about Houston Performance in Houston. Around the Austin area, there is a place named Motion Dynamics, I know they specialize in Mustangs, but I have no idea if they do tunes or have a dyno there. My friend used to work there, but I have never asked if they did tunes. Hope this helps!! See ya on Lone Star Stangs!!
I agree with my friend above; register there and that's where you will find alot of info about local TX shops. I replied to your thread in the SW forum and I'll say it again. Murillo did one hell of a job on my ride and pretty much the man to go and see for dynotunes IMO...