RMS is the recommended continous wattage (w/ amp otherwise the sub isn't really gonna make much sound
). on a sub like any JL makes, they're under rated a little, like the sub i have w/ 75 watt RMS, i run it at ~135 watts. maybe i run a little too much but it's still not really distorted. the max wattage is just that, the max it can handle for a burst (there are amps you can buy that will deliver big amounts of power for short intervals). Most manufacturers void your warranty if they find you've gone over these numbers. Though I believe JL still warranties their subs as long as you don't go way far past RMS. Like my sub, if it was new, it would still probably be covered under warranty.
