I started on my door panels the other day. I went to my local upholstery shop and picked up a sheet of the 1/8 inch thick cardboard. So far I have just cut out the cardboard by using the old panel as a template but I made sure I left a little extra and trimed it off as I test fitted the panel. Next I will remove the metal that the factory pushed through on the old cardboard using my 4 1/2" grinder and a metal cut-off wheel. Once that is removed I just have to rivit the cardboard to the top door plate that holds the window felt and cover with foam/vinyl. I also painted my lower panels with another coat of black, so they are ready to go. Here is where I am at right now and I will have the rest of it done and posted by the end of the weekend. BTW, the lower panels I paid $8 for at the junkyard and the rest of the material didn't cost me more than $30. So, it's pretty inexpensive.