I've had this project in mind for a couple of years but just now had the opportunity to get to it. Originally, I had planned on replacing the trunk lid altogether with 1/8" (3mm) diamond plate but then I started thinking about the thinner, cosmetic stuff and the idea of making a skin for the existing lid, which is mangled but doesn't leak a drop. I bought a slightly damaged 4' x 10' (1.2 x 3m) sheet of .025" (0.635mm) aluminum diamond plate a few days ago and got home early enough to get into it today. Here is the aged-to-imperfection front of my PUP. The lid has looked like this since I bought the PUP 5 years ago. It had a hole in it which I filled with caulk back then. Removed the lid and drilled out the rivets holding the piano hinge on. Cut the sheet down to 84", the width of my PUP. I then cut it in half lengthwise, one piece for the lid and the other for the front panel of the PUP. Doing the trunk lid, first fold on the end. Made cuts at the ends for the overlap. I wanted to leave these on so I could overlap them on the corners. The final fold with a piece of scrap wood cut to the length of the lid. And the first test-fitting. It's going to need trimming and the sharp edges smoothed down before I permanently attach it. Looks pretty good in rough form though.