That’s part of why Garmin released the Gi275, it fits the existing panel and replaces more existing instruments than just a G5. Also, will you be connecting to a GPS unit for NAV or an autopilot, that will weigh into the cost as well. Unfortunately the G3x will cost more in the long run both in labor but more so in additional parts. Primarily a custom panel is needed and is going to cost $1,500 to $3,000 depending on what plane and what shop is doing the work. The nice thing about the G3x is that it can replace a lot of the existing round dial instruments to reduce failure rate of mechanically spinning instruments. Prior to my upgrades, over the last two years of ownership, I installed a new DG, then the AI failed so I installed a G5 and shortly thereafter the electric turn bank indicator went south and the DG was starting to drift a bunch... I was going to go dual G5’s but I still had to contend with failing turn bank and a full glass panel was the ultimate goal. While it was more expensive than just dual G5’s or Gi275’, I got what I wanted in the long run. I figure why do the work twice and pay more but your pocket book will dictate the end result. It’s chepaer to pay some interest for a loan than to redo or upgrade only a short while later. FYI, at this time the 275 can’t be used as a backup to the G3x per the STC and I suspect that is because the 275 cannot control the GFC500. It is in the works but no definitive timeline has been provided.
