Those are the only way to do it as the tunerlist does not support the aux function of the update list.
i thave the £40 3.5mm jack one and so does my bropther they work a treat, and it depends how you wire it, i just have the cable coming out my glove box, , basically all it does is translate the audio signal from the earphone out put into a cd changers signal so the headunit can play the signal, pluging the update list audio cable in does not decode the signal so wont work on the tunerlist.
the only prob withtis is you need to chose between a CD changer or an aux input, but its piss easy to install if you have small hands. its just plug and play basically.
also it wont charge or operate the ipod the £30 one, dunno about the £75 ipod one) its just the same as puggin speakers into the MP3 players earphone sockets.