The Jackhammer 6000W RMS car sub-woofer is available with a dual 2 ohm voice coils or dual 4 ohm ones.
I think it can destroy all the glass in a car and in other cars nearby.
The 10" sub in my car has about 150W RMS at full volume before clipping and the other speakers add up to about 80W RMS. I turn it up to max occasionally.