While Avidynes IFD540 plug-and-play GPS navigator is opening the flood gates for removed Garmin GNS530W systems, don’t look for steal deals. Private sellers and reputable retailers-which we define as established avionics shops with Garmin and Avidyne dealerships-sell the units for $8000-$9000, on average. This price should include a mounting rack, connector kit, connector backplate and GPS antenna. It likely wont include a navigational indicator, the preferred standalone choice being Garmins GI106A. Its a high-quality OBS resolver-style indicator equipped with integral nav source mode annunciation. Add $2500, on average, to the project for a new one, although there are some on the used market for a bit less. The King KI209A indicator will work, too. The KI209A is often paired with the BendixKing KX155A/KLN-series GPS package found in early 2000-vintage Cessnas and in some later Piper models. Most analog and electronic HSI systems will work, too. Use caution, however, with Sandel SN3308 EHSI displays that have older software. Budget $2000 to have it upgraded so it can display the WAAS GPS glideslope signal from a GNS530W/430W.