I am not impressed with the sound system in my 09 GL 450 and the longer I listen, the more I wonder if this is just the way it is or if something is wrong. Despite adjusting all the [limited] options for customizing the sound (tone, balance, Logic7 on/off), I can't get that enveloping sound stage that most other vehicles in this class (and frankly vehicles several classes down) provide. FM radio, cds and iPod sound just ok, nothing special. The sound quality of the Sirius satellite radio is particularly bad. The compression is so audible it's comparable to listening to AM radio. I tried a couple of DVD-Audio discs - one plays and sounds just like any other CD. The other seems to *think* it's playing based on the screen showing progress through the tracks, but no sound comes out of the speakers. Both discs play fine in my home DVD-A compatible player (Oppo). I've owned Saturn, Ford, Toyota, and VW and the GL 450 doesn't sound better than any of them - in fact, the 04 VW Passat and the 94 Ford Mustang sounded much better. I just sat in a friend's 08 Sequoia and the audio was like a concert hall compared to the GL. That's just not right... Having said all of this, I can't imagine the whole sound system being faulty. Maybe something in the guts of the COMAND unit, the amp, ???? Or maybe this is just the way it is.... For others who own the GL class, does the sound system blow you away or is it just adequate?