They are made only for a SPL burp. If you want to play music on these suckers you'll have to recone them every day.
Just the same as you will blow up the engine of a drag racer, if you use him daily to drive in your town/city.
So only if you want to compete at SPL contests, this Real ****ing Loud subwoofer can be your choice. Power him up with 4 huge mono-amps (2 at each voice-coil), like the MTX 81000D. Build a huge box with even a bigger port, find that sole frequency to use, and you'll kick ass of those Stroker subs. But otherwise stay far away from the RFL.