I found an exception to the list. My 2002 X5 3.0 d (European model) does have Xenon lights (level 5) but has what BMW calls the basic sound system (S675, i.e. 6 speakers: front & rear doors, dash tweeters)

A North American E53 would have the next level up: HiFi (S676, i.e. 10 speaker: adds rear door tweeters and front door corner tweeters and amp in the left trunk storage area) as standard.

The DSP version is a level beyond the HiFi.

As such, no wiring in the back to add a CD changer, NAV or similar or to add a Silver Line / DICE / Audiovox iPod interface. A shame but retrofit isn't work the time and expense (and I do like retrofit projects).

So my Garmin GPS on a suction cup is quite fine. One CD in the dash at a time is OK too.