So the polk DBs are out, Dan is now employing Two 12" Diamond D6 subwoofers - they came out to $160 each after my discount.
We are tying to keep at least partial functionality of the trunk this time unlike the last setup which left no room for cargo. So we are building a sort of wind tunnel with two or three fans pushing air in and having it channel across to the other side to vent. We are also hoping to get some acrylic windows in there as well.
The last cute thing I insisted on was the red neon glow from under the floor that glows up on the face of the woofers.