hmmmm

400watts to a w3 is pushing it isnt it? i had 300 to mine. last i read they take 250watts? im not sure about the v2. i would rather get a pair of w3s than a single w6.

and dBs? that really depends on your box and the install job... its really hard to just give out a good number. but that pair can probably get mid to high 130s? even a rare low 140? just a guess.