yeah, you gotta be specific sometimes, like on a taurus, its hell just to put a cd player in, gotta swap climate controls and rund stuff from the trunk tuner up to the dash and yeah... but its still 55+parts if applicable. but if the factory plugs has been hacked its extra. mainly because its such a pain. now if the factory plug was left in there and an integration harness was used it'd be a different story.
you mentioned that you had gotten an accurate wiring diagram, if every was indeed wired correctly and you did not get power, check the fuses. sometimes there is more than one fuse for the radio circuit.
1989 Ford Ranger XLT: Extended Cab, 2.9 V6, 5-Speed
MECP Advanced Certified Mobile Electronics Installer