Did you look at the date of the post...I doubt he still has it after fifteen years and, even if he did, he hasn't been on the forums in 12 years. You might want to look for one elsewhere.

 

Been looking for a cover myself. Used covers average $50, plus another $20 to $25 for shipping. Too expensive for my budget although I still needed something to cover the subwoofer and amplifier.

I ended up cutting a 1/4" thick sheet of Masonite to 40-1/4" wide x 16-1/4" long. Plywood might sag even less than Masonite. No fasteners needed. The inboard edge slips underneath the headrests. The outboard-side edges lay on the oem cover shelves which could be "velcroed" but I'm not gonna. As is, it isn't going anywhere.

I could have extended the 16-1/4" dimension with a curve to match interior trim but it isn't necessary. Both speaker and amp are hidden from view.

To minimize heat, I'll probably paint it light gray instead of black.

 

Pretty creative fix to use particle board for a rigid cover. If your still looking for a back cover for a cheaper price I'd check junkyards