Anyone that's been following this thread and waiting for Gauges to work with a 2018, there is an updated installation guide for the RR1 and SU1/SU2 harnesses that involve cutting 2 wires on the harness and connecting them to the climate control connector. I used a couple of T-taps onto the original climate control harness.
Hurray for PSI gauges that actually tell me what my tires are at!