texasjohn said:
The way to tell between a) and b) is to look for the surround modes in the options. If you don't find DSP within the BASS, TREBLE, BAL, FADER menu you have system b).
Just to clarify this - the DSP option isn't within the radios "Bass/Treble/Bal/Fader" menu. The DSP option will be found at the top level of the cars OBC, ie: When you go into the computer screen you'll have options for the "Navigation", "Telephone", I think the other one is "config" and then you'll have a "DSP" option.
Working from memory so these are approximate