Andrew,
I have the Pioneer AVIC-Z1, great nav unit and so on. I also bought the Pioneer CD-IB100II Ipod Adapter. It works on the Z1s touchscreen, controling the Ipod so yuou do not have to hold the Ipod in your hand. If this is the Ipod adapter you are getting then forget it.
It works ok but its features just suck. We used it a few times and it is basically worthless. You can only scroll one song at a time and it is VERY slow! If you want to get to a song or artist that starts with M you have to scroll one at a time all the way to M, it will take a couple minutes easilly.
Many people have complained about it. Hopefully Pioneer will do something about it. I have mine installed for around 4-5 months but have only used it a couple times. You would be MUCH better off getting a cable to plug the Ipod directly into the AUX connector on your head unit and controling the Ipod itself.
If you are dead set on getting it and want to save some money I will send you mine for $25 + shipping. That is half price, it has been used 2 times - other than that it has been driving around in my ST for 4 months or so.