Can the Garmin GI 106A be used with a Garmin GNC 300?
Yes, you can use the 106A for GPS right/left indications. As the 300 does not give glideslope you may want to use a GI 102A (no GS indicator).
Is the Garmin 106A CDI - Vor / Loc / GS fully functional with a Garmin 420 WAAS?
A 106A CDI - Vor/Loc/GS will work with a GNC 420W GPS but you are limited to only GPS and WAAS approaches. You would not have Nav VOR, ILS or glide slope capabilities.
Does the Garmin GI-106A CDI- VOR/LOC/GS work with the SL-30?
Yes, the GI-106A is commonly used with the SL-30.
will all functions of this Garmin GI 106A VOR/ILS/GPS Indicator work with the garmin GTN650 and is it a good match for IFR certification
Yes, The GTN 650 will support all functions of the GI 106A. Garmin recommends the GI 106A for IFR flight.
Does the Garmin GI 106A come with the installation kit?
Yes, the connector kit is included.