I'm sure they have a decent way to move around tracks although I don't know exactly how. The head unit just sends out the commands and the phat box (or whatever) interprets them however it needs to be user friendly.

I also don't think the compatability issue is an issue. Its just a matter of emulating the CD changer. Certainly couldn't be that hard and there is no reason that a final product would not function transparently. And I'll say it again, there should be no reason it should be slow. In fact it should be faster at changing than a CD changer:)

Alex Lear