Can't help with any specific shops in that area, but keep in mind that our cars are still pretty new, so finding a shop with specific 718 experience will likely be extremely difficult anywhere in the country.
With that said, it does seem to be very similar to the 981 and 991. The primary difference I've found so far is the tweeter situation. It's in the same place as the 981, but getting the vent out is different.
If you haven't seen it yet, I have lots of pictures in my build thread. It may be helpful to a shop when you find one.
https://www.718forum.com/forum/electronics-audio-lighting/18416-cayman-sound-system-upgrade.html