I'm not sure now mate, was a long time ago when I researched all of this! Everything I know is in one of my previous posts but I think you've got it all there. Make the most of Car Audio Centre and phone them up, the tech support on the phone was brilliant and they will confirm everything you need. If you don't want to buy it from them there are no obligations so make the most of the great service anyway. I bought it all from them because they let me haggle a bit to price-match other prices I found online.
I have also since found out that the volume can be controlled by sliding your finger over the screen when you have the screen turned off to black (I always fade it when listening to music) so that't good to know. In response to the last comment about it being a bit of a fiddly menu, I agree it is a bit fiddly to navigate within your ipod / usb but once you've selected a playlist / album it's not really a big deal and it beats trying to do it on your ipod whilst driving which is what I used to do in my Corsa
Hope that helps,
Dan