Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
MDF under the carpet, screw into it through the amp and carpet. Might work?
Kinda like trout said, I would take MDF and spray with bedliner or some kind of protective coat (from water) and place MDF betweem your sound cancelling materials, and the factory carpet. Lay factory carpet over the MDF and then screw the amp down through the carpet into the treated MDF. It won't go anywhere. Protective coating on MDF is to keep wood protected from moisure if carpet/floor where to ever get wet.
The shop that did my install used construction adhesive to mount MDF to the back wall then mounted all the amps and stuff to that.
There's nothing there.
There is a velcro strap for like $5 at home depot with both textures on one piece. Cut strips long enough to encircle the amp in a couple different directions. Then take another long piece and connect all that to the seat brackets. No drilling.
Tried it. The pic above has the H Depot velcro. It just didn't grab the carpet for me. I instead mounted it to a 1/2in MDF block of wood and then used liquid nails and stuck it to the back wall. Works perfectly and I don't have to worry about anyone kicking it under a seat.