are the replacement fiberglass bumper fillers for full size devilles or fleetwood broughms any good? by good i mean thick fiberglass, little modification to get it right and shape and angles line up good. i want to get a real good repaint the my caddy and was wondering if fiberglass ones would be better because it doesn't warp and the color would not fade. also with fiberglass the fillers could be exactly fit or contured to the body. any input would be good. also does anyone who makes them? i've seen some for sale on ebay. thanks.