Best replacement for old Cessna navcom?

Because a topic like this never gets too old

1979 172 with original Cessna (RT-385 IIRC?) radios, the NAV frq display on
the #1 box failed and the partners now finally agree it's not worth
repairing.

I'm contemplating two options:

1. Replace with a slide-in replacement like the TKM series, which will get
me a new box and standby freqs (woo-hoo!) Anybody here have those, or
suggest others? Advantage here is v. low cost to install versus something
like a KX-155 upgrade which would require rewiring, etc.

2. Replace with an IFR GPS/Com. This addresses ADF/DME, but costs us one
VOR. I don't think people will go for buying a second nav/com as well so it
needs to be a one-box upgrade.

Current stack has 2x Nav/Com, 1x ADF, 1x Mode C, Audio panel w/ marker
beacon, and an M1 Loran, all original equipment. The audio panel's getting
fussy and the ADF won't lock on to the lower-powered beacons until you're on
top of them. If it was up to me I'd yank it all but I've got 4 other guys
who fly less and almost never fly IFR so they're less picky.

Best,
-cwk.