Like cars, the budget determines how good it can sound. I use my smart phone as the source and wifi an online music service like Tidal. The lowest quality sound they put out is CD quality.
I do have a double DIN head unit to control everything, which feeds into a Zapco DSP-VI II processor then into 4 high-end Z-AP Zappco amps. One for the pair of Legatia X1 tweeters (A-pillars), 2 for the 4 Legatia X6 7.1" midrange/midbass drivers(doors) and one for two 12" subs under the rear seat in a custom tuned enclosure.
The DSP has time delay and actively crosses over all the speakers, so the bass sounds like there is a drum set in my dash. It's stunningly clear even at high volume.
At this level, it's all about component selection and installation quality. Good sound cost money, sir. How good do you want it to sound?