Maybe, Roger. A couple quick observations (none FMS related, as I didn't get that far)
1)the realityXP configurator boogers the RXP install and doesn't put it in the right place. You have to go into the simobjects/airplanes folder and after running the script you will see another 1900D folder containing the updated interior model and panel c0nfig. I just over-wrote the ones in the main 1900D folder and voila! RXP 530 installed.
2) VC lighting works via switches on the overhead panel. Minor gripe (and similar to that of the B200 and C90) is that the blue panel floods are waaay too bright. A dimmer bitmap is definitely required there. Not the cabin flood, but the blue lighting that resides over the panel itself. I always thought that was some kind of emergency lighting but maybe I am wrong.
Performance FPS-wise is excellent on my system. I turned off the Avidyne they installed in the panel as I have no need for it, and will most likely replace it with a weather radar.