difference in audio systems and nav question
 

hi all
new to the forum and looking for my first rx8....
in checking into several cars it appears that there are at least two maybe three audio systems that came with the cars;
standard single cd?
6 disc changer
Bose version of the above?
can any and all be fitted to play mp3's?

on the nav system, I am trying to find out if the unit offers enough functionality to warrant purchasing a car with it...if not then my options are much more open. if anyne has a comment on their system I'd appreciate hearing them, but even better if someone has a scan of the owners manual pages that covers the nav system I would be very grateful to receive it.
thanks to all
c77

errrr....my specific questions regarding the audio systems are 1 how do I identify the different systems and which is the best (i assume the Bose?)
and
2) if the unit did not come equipped for mp3 can it be added on?
thanks!