So I wanted a sub in my estate BUT I wanted to keep good space in the boot. first picture is with cd rack removed.
the next picture shows the measurements of the box.
you have to shape the side to the rear of the car I cut small bit of chipboard for this as you can see.
you will also note that the rear right hand side as you look at it is stepped so it fits into cd hole(see next picture) once you are happy with fit car body filler the shaped side.
I also fitted acoustic foam as you can see on the inside of the box and I ran a silicone bead around the inside joints.
Once car body filler is rubbed down and you are happy with how the box fits back into the hole(I made it fit all the way back into the hole) you can paint or cover it
Put speaker cover on so things in the boot don't make holes in your sub
Thats it hope it helps......
