I installed a 2000 Camry single DIN Toyota branded radio in my 60. They also came in early 2000s Corollas and seem to be about $10 at the junkyard. AM/FM/Cassette + optional trunk mounted CD changer. You can wire the CD changer input for Bluetooth, which I’ve done. So I have radio, tapes, and I can set up some music playing from my phone. No adapters, no visible wires. I bet it can be installed in a 40 as well. It’s just a matter of wires for battery power (if you care about preset radio stations), ignition power, speaker wires, and ground. The Bluetooth system I cobbled together takes more wiring.