[5lugnuts]

I think you have about eight to ten inches of unseen depth below the plywood floor under the drivers seat (behind the battery and under the seat). Woofers are none directional. Maybe you could build a box under the floor out of plywood that would conceal and protect the woofers and replace the hole you cut in the plywood floor with a grill and cloth or carpet . Then, put your woofer in the box you built under the floor.