Gat damn. I love the new cars! They sound fantastic on my cans, though I do lose some of the finer details when using my speakers. Each vehicle has a very unique sound note and overall personality and feel. I like that they have that throaty gargle and spit in the ultra low speeds and in idle as it should be, though perhaps a touch under pronounced when accelerating. The Onyx sounds among the craziest though, with a lot of layers of unique audio notes including this subtle intermittent turbo hum/buzz in the background.
Just to re-iterate something, if you're using your headphones straight out of the DS4 and un-amped and without a DAC, you will be losing some of the finer detailing and proper soundstage. You also get some weird audio skipping and other notes that don't quite sound as they should. But still, the differences are not as pronounced as I expected them to be, though they are definitely there.