What is recommended to replace the original rubber matt inside the car behind the backpad mine is all cracked and filthy

alternatively should I reuse the original rubber matt is there a way to repair it?
it is split in multiple places from folding it

I was considering Dynamat , Klimat, or Noico 80 mil butyl; Amazon

Suggestions and advice needed

disregard/deleted - my post was about the other side of the firewall.

My 914 had some sort of sticky dynomat installed. I'm eh about it and wish it wasn't there. SO much work to remove it though. Would rather have a decent stock/heavy pad.

that's an interesting point I wonder if mine can be salvaged it has so many splits from being in storage

Clean it & patch cracks with duct tape (both sides), it's good stuff !

Modern products work better but are more permanent. You really have to stick the pad to the metal to damp the sound.

Yes it can be salvaged. Easy to put in and remove if you decide. Duct tape will do the trick.

we make great copies of both the tar pad behind the vinyl covered back pad as well as the engine insulator pad on the firewall in front ot the engine