Not sure how much of a music enthusiast you are but my 2009 X5 (manufactured in 2009) came with the premium sound and it is well worth the money. The bass (two subs under front seats) and highs are truly exceptional - the mid range is great but could be better. I also drive a 2006 M3 cab with the Harmon Kardon system which cannot hold a candle to the X5 sound system. One of the best that I have ever heard in a stock system.

I recently read somewhere that all 2009 X5 beyond a certain production date (Feb 2009?) were to have the premium sound installed due to technical compexities on the production line. You may want to check out inventory at other dealers.

I hope this helps.