Click HERE for some info on my website about replacement '03-'04 Cobra window stickers. I'm not sure if Jeff is still doing them, but you can check with him.
I got in touch with someone over inventory at Ford a few years back. They printed out a new sticker for me (peal and stick etc) and sent it to me in the mail all free. They only keep it on file for so many years, it will probably have to be a reproduction now