[wildthing]

Any DIN1 should fit. It's now a matter of preference on the colors of the display. Some folks like the look of the Porsche Classic stereo. I have an Alpine CDA something or other. $105 at Crutchfield some years ago. Your existing wires may work. But they are 40 years old now and the constant opening and closing of the doors may have broken them (happened to my driver's side speaker wires). I replaced the speakers but did not want to drill larger holes so I stuck with 5.25 woofers and a separate tweeter (Focals I believe) in the stock holes (88).

Amps may be necessary for a clean signal since the sound of the engine drowns out the stereo. Once you are cruising at 3K RPM you will adjust the volume. Even more so with upgraded exhaust components. Fortunately, Alpine amps are not expensive. I forget what I have but it's not Alpine. 4-channel and it powers the front and rears. If I were any more serious I'd get rid of the rears and install a shallow sub.