Carpet backing, carpet Options

[Medtner3]

just recently got my 10 piece carpet set from 914Rubber it is beautiful

However, there's no backing to the carpet and the original had a sort of clear plastic perhaps the same material that is inside the door panels

Would anyone have any recommendations as to what would be a good backing for the carpet?

[rjames]

I don't recall any plastic on the back of my old stock carpets, but It's been awhile and they are long gone.

The plastic sheeting behind the door cards is a vapor barrier, which wouldn't be needed on the carpets. You should be able to lay them down 'as is', using the grommets to hold the main floor pieces in place. It may take some time for the all of the pieces to lay down fully and conform to the shape of what they are covering.
I didn't need to, but some recommend using a light adhesive spray to hold things in place, especially for the pieces that go over the longs.