They're all 430 - 500 watts.
Guys, I have learned an awful lot about subwoofers the last 9 months (but am still a far cry from being an "expert)." One of the things I've learned is that the power of the amplifier, by itself, is no indicator of how good a given sub sounds or how loud it will play.
I know that I, as a layman, would tend to judge a sub by how low it would go and how much power it had. The common misconception is that a sub with a 1000W amp is better than a a sub with a 500W amp, right? 'Tain't necessarily so. What matters is how the driver (efficiency/throw,etc.), cabinet design (sealed or ported/internal volume), and amplifier (power/EQ curve/etc.) are integrated.
This past weekend we were testing a sub and, much to our surprise and disappointment, it was bottoming when it shouldn't have been bottoming. We discovered that the new and untested amplifier (we were hurrying to get things up and running and were running late) was delivering nearly twice its rated power.
Because of this, the poor thing was trying to deliver unbelievable SPL at under 10 Hz which resulted in bottoming.
It has turned out to be a good thing, because it will allow us to reduce the cabinet size from 24"x20"x20" (HxWxD), to a less intrusive 20"x20"x20" which will prevent the bottoming while reducing output by only about 1 dB above 10Hz.
Point is, you can't judge a sub's performance by any one spec. It's how all things, driver/cabinet/amplifier, work together.
I am still a contented EP-500 owner. Just yesterday, I was playing some music with strong (and low) bass (Stanley Clarke, Billy Cobham, etc.) and I was sitting there just delighted with the tight, clean, smooth bass the EP500 was delivering. IMHO, when integrating all its parts, Axiom got it right with the EP500.