My panel radios are trash. Are there any available options that are less expensive than a complete radio stack replacement?
In a word, Yes. However, the usual two-word caveat applies: “It depends”.
If all the wiring, antennas, trays, etc. are still in good condition, and if no major functional improvements are required (such as IFR GPS), there is indeed a lower cost route to a new digital-display radio with flip-flop frequency selection (and sometimes frequency storage and some other added features). This option is to purchase and install one of the slide-in replacement radios made by TKM. In most of the Beech Aero Center planes, this will mean considering an MX170B to replace a KX170B.
TKM makes much of the test equipment used by avionics shops. Their equipment is held in high regard. Their radio production is both low-volume and low-key, limited to their line of slide-in replacements and one digital indicator. The Avionics Links section contains a number of links to detailed specs and info on these radios. The TKM radios are available at discounted prices from nearly all the major suppliers.
By far the reports by owners of these radios have been very positive. In at least one confirmed instance, a used MX170B proved to sound both stronger and clearer than a much newer Garmin 430. This was true on both transmit and receive. The MX170B was purchased as a slide-in replacement for a KX170B that had been retained as a #2 during the Garmin install.
A small number of the MX170Bs have experienced problems, which were quickly and very economically repaired by TKM. In most cases TKM repair costs have been reported to be one-third to one-fifth of the typical repair cost of King radios (for example). If you find an MX170B that has slightly yellowed lettering and buttons, the factory will refurbish the face and install new buttons, making the radio look like new, for only $80.
Here is some contact info for TKM:
TKM-Michel: TKM, 800-233-4183; 480-991-5351