I replaced front and rear bumpers of the Matchbox several years ago by cutting a length of pvc guttering...drilling holes to match where it meets the supports and holes for the end caps. You then paint them flat black. About 25 lbs total less wt. Finally found the photos.
http://www.indycarz.com/forum/attach...0&d=1427959090
http://www.indycarz.com/forum/attach...1&d=1427959122