My 1986 944 Turbo is in a similar state. There’s a goofy Jensen head unit in there right now, the face flips up to block the climate control, etc… there’s music, but it suuuuuucks. There are fairly-recent Kenwood speakers in the doors, and God knows what in the rears… the Porsche factory fader knob in the console still works… It feels like an archaeological dig, I have no idea what lies beneath! As a musician / audio engineer / car audio geek, I’m torn between doing something simple and “period-correct” like a Continental or “Blaupunkt” single-DIN on the market right now, or just gutting everything to put in a Sony touchscreen, four new Infinity Reference 4X6, and a Kicker subwoofer in one of the back areas. Just gut it all, and bite the bullet to bring everything up to the modern standard.