Also, you may at some point be interested in charging the ipod as you roll, esp on longer trips, you may think about trying a docking type cable that has an audio out and charges the iPod.

Maybe someone can confirm this, but it's my understanding you get a little higher output when using one of the docking cables, instead of a headphone type 3.5 mm cable.

In other words, you don't even use the volume on the ipod at all, it's like a true pre-out using the docking cable, so it's like 100% of the signal going into whatever receiver/head unit you have then amplifying it.