Your damaged spoiler is the perfect candidate for a little known repair product known as Polyfix. It is an FAA approved product for composite repair. I have used it successfully on fiberglass and other composite/plastic repairs. The only retailer I know is Pegasus Auto Racing Supplies 1-800-688-6946. I first saw it demonstrated several years ago at an SCCA regional race. A formula vee driver lost the nose of his racecar on the first lap of the first seesion, only to have the rest of the field run it over. Corner workers scooped up the pieces and brought it back to the paddock. An neighboring Atlantic team had this stuff, and after a bit, had re-assembled the nose piece like a jigsaw puzzle. Mounted it back onto the car and ran the rest of the weekend. Neat stuff.. a little pricy ($40), but well worth it.