I've read quite a few times that you really can't put much more than about 250 watts into a tempest before you reach its excursion limits. Since I have an 800 watt amp, I would like a driver that can take alot more power. However, when I model a 120L vented enclosure tuned to 25Hz using UniBox404, at 600 watts, the Tempest doesn't reach its Xmax at anything above 20Hz which is all I care about. Is the 250 watt limit only apply to sealed boxes? Am I doing something wrong? Is UniBox correct?