you hit 140 at what freq? If you want to hit 145 in the 30-40HZ range your going to need to go ported, otherwise your going to need some serious power... hes a pic of what the output from the sub box is going to look like from winISD Yellow line=Sealed Box White Line=Ported 6cubes tuned too 32HZ http://s257.photobucket.com/albums/hh201/h...tforlucky-1.png Vented Box peaks at 36HZ, box is tuned to 32HZ 6Cubes 3000wrms(1500WRMS per sub) Sealed Box Peaks at 74HZ, box is 2.8 cubes, 3000wrms(1500WRMS per Sub) Subs are 2 Fi Q 12's D2's Basicly your going to get ~10db more output at 30-40hz in a vented box than a sealed box.