There is nothing wrong with Pok's 2004 or 2005 line up, it's the people who don't know how to set there amp's gain to match the output voltage coming off the back of the head unit from the pre amps that destroy these subwoofers. The RMS of a name brand subwoofer is stated in plain english for one simple reason, and that is because it is the maker telling the consumer to not exceed the RMS limit, because continuous exceeding of the limit will eventually cause damage to the sub. How long it takes to damage the sub, all depends on how much power is being used in excess of the RMS limit.
If that isn't the problem, then you may want to start observing your electrical systems power source not the battery , but the battery's power source, the alternator. If you alternator isn't supplying your vehicles electrical system with enough amps to compensate for how many amps your amplifier(s) are drawing, then you will starve the amplifier(s) of the power it needs to supply maximum power to the subwoofers, forcing the amplifier to compensate for the lack of DC voltage with AC voltage. This will rip any car audio subwoofer on the market apart no matter how strong it is.