jl for sql more bein sq than spl....but if you're more into spl over sq..the the DD is your choice..but i can tell you that the DD wil absolulty slaughter the w6 in spl.
Yeah the DD 9515 is the 15" and it will kill just about any 15" sub if you compare its SPL ported. But the JL 12w6v2 will win in SQ though. The JL 12w6v2 can have good output ported built to jl specs.