We decided to take our 2017 GT Performance Pack to Rabid Customs after I attended an open house they had recently. Plus, their tuner, Randy, did the majority of tuning on my Firebird over the years and he does great work on a variety of platforms.
Rabid Customs is a new CR sponsor for 2020 as well and can do everything from mods/builds and tunes, to restorations. Their facility is very nice and modern, including use of a loaded dyno and all the amenities of being owned by Ricart (they actually flashed a Ford TSB software update to my car while there for the tune!)
We dropped the car off for a several different tunes, and since I have HP Tuners, am able to load them myself as needed. They are:
93 octane (dyno graph attached)
93 octane with ghost cam (gives it a choppy idle, for car shows and such)
Flex fuel/E85 (should pick up some more power on straight E85)
The Mustang just turned 12k miles and it's only mods are a Corsa cat-back and K&N drop-in filter.