I have a couple of questions pertaining to the exhaust manifold. First, what type of metal is it made out of? it almost looks like its concrete but mine like everyone i've seen on a w201 shows rust or discoloration. do these typically ever need to be replaced and does this discoloration mean that its rusting out?, my EGR is also doing the same thing. I'm also thinking of painting it with some VHT high heat exhaust paint in maybe a nice metallic silver and following the "bake on" directions. anyone ever have any experience with this product or painting exhaust parts before and any advice there? thanks.