I like it..
I did a rear tray like that in my 75 Cutlass.. but used vinyl like the seats.. and punched holes in it for the speakers. looked factory..
used a fabric punch. and mapped out the holes for spacing and punched them out..
The rug works but will effect the highs, you might not be a big deal with sound bouncing off the rear window..
kinga like this.. only this looks like it's for a 4x6 or 4x10 and I used vinyl not plastic and smaller holes and not as many.. you couldn't see the speakers from above.. just like dash speakers