The JL W7 s a superior driver all the way around, (when compared to a PB12 plus) when comparing to most any commercial subwoofers.There are very few subwoofer drivers that can even match its performance. More or less, only the TC Sounds LMS drivers have shown a more linear BL curve and similar power compression capability. However they give up serous efficiency with much higher inductance when compared to the W7.
Not bad for a design released in 2001...