The Toyota tape player loom has two connectors between loom and tape unit. The replacement Sony CD (CDX-GT160/260) has its own single connector with colour-coded wires attached. Will I have to determine all Toyota wire functions, and then cut and join to Sony connector?
Yes. You'll need to find a wiring diagram for the Toyota that shows which colour wire does what, and then hook them up to the corresponding Sony wire as shown in the instructions.