It's sad to see some answerers here (by no means all) who otherwise regard themselves as
audiophiles
proclaiming systems the car came with are high quality. The incredible amount of DSP used that F's up & homogenizes the sound FAR more then a quality system w/o it is always just sad. The first time I heard the Burmester system in a Panamera not even moving, drove the point home. All the optional settings (some double digit no.) only made it worse. If you picked the dead neutral one, it was grey, uninvolving & somewhat more detailed then inexpensive crap but nothing impressive by any standard. The ML system in a Lexus was better (after they completely engineered it a couple of years after first reintroducing it) but nothing like as good as say, the Focal utopia car audio installed with quality amplifiers (theirs or someone elses as good) Someone earlier mentioned the Milbert which is the ne plus ultra. I heard the B&W Diamond tweeters in a BMW & they were discernibly better then the ML but the DSP always throws a blanket over the music that would be gone w/o it. The Revel was revelatory in its detail & dynamics (for a DSPed system in particular) but ripped your ears of with those aluminum tweeters. Taming it in the systems described always results in sophisticated (at best) blandness.