W7 hands down, for me its a really good all around subwoofer.
IDMAX is very effiecent, great sq. But not as loud as the W7. W7 has a better lowend impact.
My Tru Hammer h-1, is giving it only 600-800watts. If i get a pair of IDMAX. Drop it to 1ohm, they will be getting 750watts each. So they will be playing quit well...