FWIW the extra speakers in the rear pillars are the main reason we decided to order Premium Sound on the X5 that we just had built. The way we tested is to use the same iPod plugged into each system. We tested using the same songs (with high bit rate compression), back to back on two different X5s at the dealer.

Frankly I would have been happy with the Standard Sound package since I rarely listen to the radio/music except on long trips. But my wife drives the X5 by herself more than I do and likes to listen to music. She liked the surround sound feature along with the rear pillar speakers.

Funf Dreisig