has anyone tried to build a custom box in a fc by making a hole in back of the seats in the wall that leads to the top of the hatch and also gutting out the storage bins and connecting it to the subs for a resonance (sp?) chamber sorry for my horrible description.

 

I made some for 10's that replace the bins. I don't think there is enough room to do what you'r thinking. The plastic thing the bins sit in is only about 6"on that front face.