Thorney in Arizona. And you've been here long enough to know about McMedics. Also @March_MotorsportsDFW in Dallas, @L.A.R. in CA, Cannonball garage in Chicago. Plenty of options if the shit really hits the fan.
Ask local GT3 race teams who they use for the engine interval work and go with them, people have mentioned Re Performance, i know they look after some GT3 engines