My advice would be to get your AI & DI overhauled and hang on a bit until the avionic market matures a little. There is a company oop north that will overhaul most gyros at reasonable cost (
https://aircraftinstrumentsltd.co.uk/ )
Garmin are now making a GPS / COM & a GPS / transponder Both have GPS approach capability.
If I was looking for an inexpensive lite IFR fit it would be the GPS/ transponder, Garmin NAV / COM with the PS engineering audio panel that has a built in COM. Add the two G5’s and you have a very powerful fit that gives you two COMs , ILS, VOR, GPS approach including LPV and ADS-B. Added to that the PS engineering intercom is the best in the business by far.