Wanted to add my thanks to Shane_85 and other posters after successfully adding a AUX to my 08 Aurion ATX
One note of caution is that there is a grey plug that connects into the A/C control panel located below the Audio unit, that plug will also fit into the back of the audio unit into an unused connector. Tripped myself up for a while after wrongly connecting this to the wrong place :( , but fortunately no harm done.
I used the instructions at http://au.toyotaownersclub.com/forums/index.php?showtopic=16676&hl=%20remove%20%20head%20%20unit&st=0 to get to the Audio unit, fantastic post also.
I've attached a couple of labeled photos that may help anyone attempting this project. Note that I did not use a 3.5mm jack as I could not find one of reasonable quality, I chose instead to go direct into a 3.5mm plug.
