Can't wire the three subs to four amps. Also, they can't handle the power at full tilt very long. I'll be re-doing the wall anyways, and figured I'd switch to a more standard sub size.
They're a little louder than the DDZ 18's, but not as much as I'd hoped. I know I'm lacking port length and area though.
I'm hoping six 4" coil 18's tuned low on the four 7k's will finally make me completely happy. With the next wall rebuild, I'm going all out. Steel frame welded to the truck, bucket seats, lots of change.