Audi for handbrake handle & minor coding just to enable the aux on rns then the 32 pin connector & wires etc, whole mod parts were what £12 or so then time.
No Marc's guide is just the loose cable IIRC, I wanted fixed socket.
Its not just a cable that plugs in to rear of rns like headphone jack, but can make one up for you, but be cheaper to do yourself, cause my time isnt free, lol.