The Garmin GNS430 came in 1998 and the first version was a 28V unit and a couple years later a 14/28V was released followed by a GNS430 with internal terrain database. In approximately 2006 the Garmin GNS430W (WAAS) was introduced. The list price 2019 for a GNS430 to GNS430W upgrade is USD 4495, another 300 Euro for the WAAS STC. A few hours to replace the existing GA56 for a GA35 GPS antenna and a few hours to complete the paperwork. The list price for the GNS430 in 1998 was USD 9250 and the second hand price is still very high, specially for the 430W model. In recent years we have installed many used GNS430/GNS430W and if you are able to find one to a reasonable price this may well be a fair deal. The picture below shows the second Socata TB10 that we modified belonging to Gotlands Flygklubb. Garmin GMA345 Bluetooth audiopanel/intercom, used GNS430W COM/NAV/GPS 1, GNC255A COM/NAV 2, Trig Avionics TT31 ADS-B out transponder.
8.33kHz COM frequencies and Navigation database incompatibility – ie the GNS430/W is not able to retrieve and display frequency information from the navigation database for 8.33kHz channels. This also affects Garmin G500/G1000 with older software versions. Garmin recently released a Service Advisory No: 1865A with information about this issue –1865A