Pietz Performance Tunes is a highly reputable shop in the Houston area.
I also just discovered another Mopar shop in the Houston area called Flyin Ryan Performance. I believe they're located in The Woodlands area. I live in Georgia but I've worked (and still work) out the Houston area for ten years.
I had all of my 5.7 work on my challenger dome at Doctor Differential and Speed Shop in Groves, TX (Port Author area) but he recently closed up shop because he took up an offer that was too lucratively good to pass up.
Flyin Ryan Performance has a page on Instagram. I don't know anyone, personally, that's had any Mopar work done there yet.
Alex Peitz of Peitz Performance has a solid, proven and highly reputable track record with all things performance related to Mopar, Ford and Chevy. Great customer service and best bang for the buck. With Doctor Diff shut down now, I'll be taking my Challenger to him when the time comes to get my cam package in my 5.7.