I did mine last night, 45 mins from start to finish , and I have never had the cd player and mid out before, very very easy.
I fitted the aux input in the small area just below the cig lighter in the ash tray area, looks nice and tidy.
I have a Sony HD5 and it has a true Line out so the sound quality is pretty good, much better than using a standard headphone socket.

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2005 Toledo Blue 3.0 Beige Lthr-sport-prem-clim-autodim mirrors;;
Mods so far; rear fog lights retro-fit,ractive oval tips,titanium grille set,OEM trailer hitch,mud flaps, aux audio input,non-smoker ash tray,sub-installation and a set of the 4.8is 20" replicas with cooper Zeon 4xS.Euro clear headlights & rear parking sensors.LPG Dual fuel convertion.Chrome bezel rings,Fitted uk cycle lighting board electric hook up,Sport wheel centre re-trimmed in Alcantara,
Still luvin the ride :