Aluminum. The grills I made from an automotive grill cover like the ones that every ricer puts on his crappy econobox. LOL

I cut one up, shaped the pieces to get the contours right, and then glued them in place with gasket maker. I am probably gonna paint them glossy black though...

 

how do you get the whole in the perfect location? i see that the slider just fits in the hole drilled. i have a set but am to scared that i will drill the hole a little off and then it wont look good.