My Beech C33A has a D100/D10 with a HS34 and AP 74. Nav radios are a Garmin 155 Tso and SL30. These are installed under the EAA STC and local Engineering orders(EO).
What I don't have to be IFR capable is a GPS annunciator and a GPS/NAV Cdi. Used Garmin 106 is around $2K but so is a used Sandel...