Your GT54 Is Good, the GT56 Is 150 Watts Better!
The Garmin GT54 and GT56 both put UHD ClearVü, UHD SideVü, and high wide CHIRP traditional sonar on one cable, and they read almost the same on a spec sheet. A hundred dollars separates them. Here is what that hundred buys you, and when the GT54 is already enough.