pbkid,
I have two 8" subs in airtight mdf enclosures mounted on one mdf "backplate" in the spare tire compartment. The whole assembly is held on by three bolts where the original spare tire mounting plate was attached. The backside of the assembly is covered in felt to minimize vibrations against the metal. Both of my amps are mounted on the backplate, between the enclosures, along with my power and ground distribution blocks. All the wiring is routed through a new hole in the hinge side of the door, and into the left side via the tail light. It has worked well for a year so far.........

Randy