I have access to some spares, including a heated rear seats set up.

Has anyone any knowledge of retrofitting these? Obviously seat back and base are required. Rear switch panel. Presumably it's an option loom, but where does it route?
what else would need to be salvaged? Is the standard wiring ready to accept this, or is it a LOT of work?

85 WR quattro
90 V8 Silver, 91 V8 Black, 93 V8 Lago
93 100e quattro V6. Titan, i think