An aftermarket headunit is always an immediate and noticeable upgrade in audio quality. Even stock speakers benefit from the clean power of a quality headunit
Parts used in this video:
Metra 40GM10 GM Antenna Adapter
Metra 994644 GM MultiKit with Shelf 82Up (Black)
Metra 7016771 Wiring Harness for Select 19781993 GM/Chevrolet Vehicles