I did not have the opportunity to order my car and had to pick a car from inventory that was closest to my needs and desires. I had the opportunity to test both systems back to back. I would describe the difference as being one of good vs. better. Although I thought the premium system might be a "must have" - after back to back testing - I was OK with the base system. In the end, I chose an M3 that did not have premium sound and I do not feel especially deprived. Occasionally, passengers have remarked positively about the sound in my car. If given the opportunity, I might still prefer to have the "better" system even though I usually listen to satellite radio which is not known for its fidelity. Moreover, generally, I find the sensual music that my M makes to be addicting and I find myself going for days listening only to M3 song. I would characterize "premium" sound as a desirable but not essential option.