would like to replace the cardboard like panals on doors and beside seats what is a good material to use?
You can buy them ready made from Langs and other parts dealers, or you can make your own. I'd start with a local upholstery shop, looking for heavy cardboard for the base and black vinyl for the covering.
I've heard of folks using formica (for countertop covering). I bought the premade ones from Cartouche (MACs)