It is an appreciated feature of the Pioneer Avic Z2 that I installed in my truck. I have a horrible habit of not taking good care of my CD's. With the HDD, I can purchase a new CD, immediately rip it to the HDD, then put the disc up in a safe place, in case I ever need it again.

I'm really glad this post came up. As I've been trying to figure out why my GF's Iphone doesn't work any more. At least, I guess after she re-synced it...The Nav screen just sits with "Updating Data" or the likes...This would explain it, and tells me that I should let it sit longer. Well...hopefully.