Here's the problem Larry: the vast majority of recorded audio is 2 channel, this format is difficult to properly reproduce in a home setting let alone in a car. Properly reproduced recordings require the listener to be in an acoustically good environment, use well recorded source material, use electronics capable of preserving the information encoded on the playback medium, use speakers capable of preserving the signal presented them without adding their own coloration, use speakers that provide a single point source of sound.
The sound qualities of envelopment and spaciousness you seek are really the missing audio cues that tell the listener the venue the recording was made in, be it a studio or a concert hall. These missing audio cues contain low level detail and phasing information difficult to reproduce unless all of the items listed above are up to par. Given the acoustic environment and multiple speaker locations required in a car, the attributes of envelopment and spaciousness would either be as a result of electronically being added or the artifact of poorly reproduced sound, and while maybe pleasing to the ear, it will not be an accurate reproduction of the recording.
From my recovering audiophile perspective, the MS system is a very good factory system. It is enjoyable enough that I have more hours listening in 4 months with the MS than my entire lifetime of driving listening to all other car's systems I have owned. I use the word "listening" as more than just background fill, but rather actually listening to music.
