Midwest Avionics at Lee's Summit Mo (outside of Kansas City). is very RV friendly + the guy who owns it is a former Garmin engineer. Some of the old G3Xpert posts on here are from him.
I had the panel in my Cherokee redone by Flightstar at the Champaign airport. They did a good job, price was what was agreed on and no surprises. This was 12 years ago.