[chuck92103]

The reason to get the premium sound is power. Something like 600 watts compared to 300 watts with the standard system.

Wattage is important as you won't have to crank up the volume to much avoiding disortion which is common with underpowered systems.

The X6 interior is a fairly large area to fill with sound.

There are other difference like number of speakers, DSP/Logic 7, etc. which are heavily debated. However, there is no debating the difference in power.