I live in the Knoxville area, and there is no tuning here for our Cars. There is a Tuner in Atlanta (Pressuretech) that will Tune your Stinger. However, if you do find one let me know.
Have you talked to Mark at Fastech by chance? I know he is a turbo car wizard and has an AWD Dyno at his shop. I'm in Cleveland and would be curious to see what he could do.