If you are 'careful' on the gains and/or volume knob, you aren't feeding your speaker full rated power from your amplifier, no matter what the owner's manual says. So that advice seems to have a major flaw. You could connect a Type E to a 10,000 watt amplifier, if you are 'careful' enough with the amplifier's output. But then saying you are feeding it 10k watts is simply wrong.
Acquiring so much wattage, and then going back and trying to find a speaker to handle it, id doing things *** backwards, and shows a fundamental lack of understanding of the workings of a stereo system. Its kind of like buying tires, then looking for a car to buy to mount them on.