There were three different audio systems available on the X5. I wrote a detailed post about them somewhere, but I could not find the post.

1. Standard stereo - 6 speakers and powered by the radio module (power unknown, but probably <20W)
2. Standard HiFi system - 10 speakers powered by an amp with active crossovers (~150W total power)
3. Top HiFi DSP system - 12 speakers powered by the 14-channel DSP amp with active crossovers (~330W total power)

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input