I went to listen to another Lexus GS with the ML surround sound system installed. In many ways, it sounds very similar to the Lexus standard stereo. It has the same bass weight, the same even bass response, good imaging but the whole thing gelled more as a complete system compared to the standard system which sounded a little disjointed between bass and the rest. However, the upper mids were too prominent, like in the other ML equipped car I listened to. I also preferred the standard system treble, it was much more refined there and not as fatiguing. Of the two DSP modes, I preferred surround mode off. It sounded most natural and most relaxing of the two. From what I can tell, the ML system is all about more detail at the expense of refinement. At least that's how it sounds to me.
I was also interested to see how well the ventilated seats worked and today, a warm day with warm seats, they don't cool my back at all but the legs area is cooled nicely.
I love the car. I love the tech and the drivetrain. It's quick, smooth and really quiet at urban speeds, although at 70mph its no quieter than my A6 (measured with an SPL meter on the same road). If I was going to buy it, I'd probably opt for the standard 10 speaker system and not the ML.
When I started this quest, I was convinced that I'd sit in a Freelander, love the M 825w system and then realise that I'd have to buy a Freelander. I was expecting 5Ks in the car to be my experience and it just wasn't. If I'd had my eyes closed, I couldn't have told you it was anything special at all, certainly not the M signature sound.