Here is a screenshot of the GTN 625 without the transponder controls. This gives you quicker access to some commonly used functions like flight plan and procedures (instead of pressing the HOME button to get there). Additionally you will have some dedicated data fields. It retains the + / - buttons for zoom. There isn't a way to replace those key functions with map space, but of course you'll have a nice G3X display to show moving map, charts, etc. For installation with G3X, we recommend you wire the GTX 23 ES to the G3X display.
Thanks,
Brian