I've owned both, and preferred the MTX. The MTX was much louder, and in the right box it's SQ is close enough to make the extra volume worth the ever so slight loss of SQ. But for the money, there's better than both out there.
the w6's were in custom made boxes for the w6s with both sets having a 1000.1 jl to em and the 9500s were in seperate boxes half fiberglass made to their specs and had i believe a 1500rms mtx amp to them. i heard one pair of the w6s destort while the others i only heard once and the 9500s ive heard alot and they blew both outa the water.