I tried connecting my iPod classic to the car's aux input the other day and there were volume... issues. Put it this way, to hear some of the louder music I had to jack the volume on the iPod up to full and also turn up the volume on the car stereo to the extent that there was noticeable background hiss. Even with this done, music was only on the quiet side of audible and quieter recordings (e.g. Suteki da ne from 20020220) were near-silent. From some googling (I know nothing about these things) I've estalished that this is because the iPod doesn't do line out through the headphone jack, but instead just sends a standard headphone signal. This would also explain why my previous music player (Sony NWHD5) worked fine in the same car without the volume issues - it had a menu option to switch between headphone and lineout modes on the output. From more googling I've discovered that the Pocketdock accessory offers line out via the dock connector. Does anyone have one of these, and if so does it output at the same sort of volume as the lineout on players such as the HD5 which support it out of the box?