I did the same and more and it cut my noise down about 30%, so at least I can here the radio and talk to my wife. I put 3/4" padding on the backfloor and firewall insulation as well. I posted pictures previously in my thread. Was a lot of work but glad I did it. Bought all the sound/insulation on Amazon car sound proofing. Probably $150 total.
I did this before I ever took it out, with that said, I’ve had it out with 2 in the front and 2 in the back a few times, the sound isn’t bothersome and no complaints of heat on the back panel so I’d say it helped !