The KI-256 is a gyro based attitude indicator that is an integral part of the KFC-200 flight control system. The KFC-200 autopilot is installed per STC. Therefore, it cannot be easily removed and replaced with another instrument.
Recently, Garmin has developed the G600 flight deck retrofit that integrates with existing KFC-200 systems. This is a system that integrates many flight display and navigation features not simply attitude and flight control information. The dual screen G600 integrates with other Garmin avionics systems such as the GNS430/530 providing both Primary Flight Display (PFD) and Multi-Function Display (MFD) functions. Furthermore, the Garmin GAD-43 adapter eliminates the system's need for gyro instruments such as the KI-256. The GAD-43 provides AHRS attitude/heading reference.
Therefore, there is not a plug-and-play, direct replacement solution for the KI-256 instrument only.