"Seized would indicate their ownership is being transfered to the city for disposal at its discretion"
That's exactly what should happen, after all the stereo crap is ripped out and destroyed.
This is an emotional reaction, not one based on logic. While blasting music is rude and disrespectful to the public, it is not life threatening. Heck, I'd like to see these people get the #$%& kicked out of them for this, but seizing the car is over-reacting.
Consider, I can drive over your lawn, trash your flower-bed and saplings, leave rubber marks on your driveway, lead the police on a high speed pursuit through a school zone, run cars off of the road, hauling a dozen illegal aliens in my trunk, while being drunk (all hypthetical, of course) ... and the courts would have to use DUE PROCESS to take my car. In most cases of this very thing happening, the car is NOT taken. But, if they play the radio too loud.... Not logical.