You do not need a DMR radio to get into a DMR network such as BrandMeister or TGIF. You can use C4FM, D-STAR, and others with some simple configuration on Pi-Star.
I upgraded the Kenwood SP-230 speaker using the Phits K95A and Phits GPH-X80 kits. The new speaker and foam made quite an improvement in detail and sound quality over the original speaker.
I found a deal on a Kenwood MC-50 Desk Mic for my TS-530SP or TS-830S. All that was needed was a new 4-pin connector and the mic worked perfectly.
I was able to solve an issue connecting a TRS-80 Model 100 to a Kantronics KPC-3 TNC.
I recently tried HF packet using a vintage Kantronics KAM All Mode TNC and the FT-991A. I used an RJ45 A/B switch to be able to switch between either port of the KAM or between the KAM and my KPC-3.
Using a PC-2 pocket computer to print a QSL card was an interesting project to test using BASIC and a 4 color plotter.
PE1NNZ has updated the firmware (beta version) on the (tr)uSDX to add audio over USB. This allows for digital modes such as FT8 over USB without separate audio cables.
The Yaesu FT5D’s built in GPS can be connected to a PC for off grid time sync. All that is needed is a data cable and Meinberg NTP.
The FTM-500DR is the first mobile rig with a built in speaker in the remote head and with a microphone jack in the head and body. This makes for an easy installation.
The Yaesu FT5D has a built in GPS which can be connected to other devices as a GPS source using it’s built in data port and a menu setting.