Some of us old school guys still run sealed enclosures, homie. It's all about excursion when it comes to output or extension. If you want both, you need extremes. Other than that, I'm glad that when I accidentally exceed my normal comfort zone of mechanical throw that my drivers have the ability to cope with about 3.5" of movement. Could be certain death for many drivers but it let's me play for another day, lol.I see no point in such a high level of excursion. the only time that I have ever seen it needed is when people try to play low 20hz drops in a 20 cu ft wall tuned to 50hz... subs fly then, but honestly, if you know what you are doing, what is the point of 4" of excursion?