I would like to add a little more to the conversation and just scratch the surface of DSPs.

A DSP can be a good or bad thing but is an oversimplification when most people describe it.

For years DSP were commonly known for listening modes like theater, rock, chorus and whatever else that is a preset mode. This is more or less gimmicky equalization. They are also add effects like surround sound which fills in the voids.


What a true DSP does is split up a range of frequencies in the music and send that to each bare component rather then using passive crossovers which rob the system of power and quality.
They can also adjust driver timing to improve imaging and psychoacoustics.

Even what I describe is an oversimplification but if you have the ability to bi-amp or tri-amp and implement a true DSP which is able to isolate frequencies in the digital domain it goes far beyond any passive setup.
The biggest drawback to active crossovers is tuning which I'm sure Lexus might have spent a fortune to get it right.
This is not to say you cant do better but it would be a very hard thing to implement and it would require many hours with a flat mic and a laptop to even get close.

 

One need only see the 'stock' speakers on ebay from both the ML and the non-ML to see others who have removed them, and replaced them, and now are trying to sell the old ones on ebay for big $$$...aftermarket speakers are much much better, and cheaper...some are satisfied with hamburger, some want steak..some don't know the difference...the kicker zxsum8 allows you to keep your factory head unit, factory nav, factory Bluetooth, direct the navigation and phone to the front dash speakers, and then send the rest to an amp for great music with your new quality speakers...an example is the factory subwoofer with a tiny tiny magnet(8oz maybe) which I replaced with another 8" aftermarket subwoofer with a giant 8lb magnet...what a difference!...to each his own, but I love what I have done, and so will the next owner one day...don't forget to check out EBAY to see exactly what is in your dash/doors/rear deck...tuned very well, but inexpensive speakers for sure...

 

Hey, if you're satisfied with hamburger, who are we to judge?!

I've seen the factory ML speakers up close and personal when I had my system apart. Quality all the way. What exactly do you see in those components as being "cheap" or less worthy than a speaker that has a "bigger magnet".

 

You don't have much of a clue if you have to judge a speaker by how it looks or what material it's made of or how big the magnet is.
Quality of sound is not a function of numbers or looks, it's a subjective function of what sounds good to your ears. Loudness does not mean better sound and in most cases it is a symptom of poor quality equalization that needs more volume to sound good.

The best systems are those that sound great and are satisfying at a normal listening volume.