I thought I remember seeing someone that had bought a box that installs in interior of the tailgate. I can't find any info. Can someone point me in the right direction? Curious about stuff like...how is the interior panel on the tailgate attached?...do I just pull?...what is envolved in cutting the sheetmetall for the box install? Four 8" subs across the back behind the carpet would be great. Or, perhaps two 10" subs & a small storage box flush mounted. Any comments welcome.