i have original ford radio cassette
all ford wiring as it is just replaced the speakers in door with some nice sony ones that fit directly in same housing, and replace rear speakers with some nice sony ones, direct fit, you wouldn't even notice they were any different, just change the connectors for spade to join them in. keeping original wiring is fine

as long as you don't plan anything techno or hardcore then for me they are adequate, totally perfect for the radio music, classic fm, radio 1 and 2 its all great