Yes the premium satnav has a single disc slot in the dash but this will read MP3 discs. On the Titanium, you can spec an additional 6 disc autochanger (or it may come as standard) but because of the Recaro seats, this is not possible on the ST/RS. I have a feeling the Bluetooth/USB kit is also now standard with this system, which means you can plug in an Ipod or memory stick fully of MP3's and just use this. Check with your dealer though as this used to be optional.
The Denso and new Blaupunkt touchscreen satnav systems both support CD's filled with MP3 files. The latest non-touchscreen satnav system with the SD card slot to the left of the screen will also play MP3 filled CD's...well according to the manual