Euhm, wtf. (they maybe look the same on the outside, but i don"t think they are the same on the inside of the motor, and it has differen soft parts) And the Level 3 has more BL and bigger xmax.(and probably more power handling.) Higher BL and more Xmax means it has more potential to get louder. The Re SX has lower Fs, and Lower Qts, which means it has mre potential to sound better. The Dc level 3 will sound good, even real good if u make the right box for it.(and it should be more then loud enough, is it's for SQ...) lvl 3....upgraded SE? lvl 4...upgraded MT? Upgraded mt? The MT's can handle 3-3.5k watts or even 4k in some hands, the LVL 4 can't.(the level 5 can.) Cause it's a big, inefficient waste of ferrite The MT is a solid driver, Scott knows how to design woofers as he's done MANY.