Hello all!! Very seriously considering the 09 Mazda 6. I've been trying to find out some specs on the radio (Sirius, LCD touch screen) and am having trouble.. Anyone have any links to where I can find detailed specs about this??

A few (of many) questions are, what's DVD based Nav? If it's hooked up to Sirius, why do I need a DVD? A DVD of what? Each city?

Is there an option to add a hard drive? USB input? (I know there's ipod input).

Thanks so much....