Questions about Sound Deadening Material

I used a glue down sound deadener material only after I was done replacing the floor pans knowing I would not be planning on pulling it up at anytime in the future.If your car is still in progress you may not want to use something you'll have to undo in the near future.As far as the plastic behind the panels that's a moisture barrier and yes you want that.If your not concerned about factory correct.You can use heavy plastic sheeting from a roll available at most hardware stores.Just cut it to size and use a bit of weather strip adhesive to hold it in place.