Cars from this era are a blast to drive, but cutting up the dash to install an aftermarket stereo that offers modern playability is going to tank the resale value. A collector is not going to want to buy a car that has been cut up and modified, no matter how cool the stereo installe...
The fastest way to connect an aftermarket pigtail to an OE harness is with crimp connectors. Simply strip two wires, slide them into a connector, and then crimp it. At this stage, it's vital to connect each wire properly. Some head units have wiring diagrams printed on them. Every factor...