We've got MAC long-tubes with the HTS coating - I was debating on whether or not to spend the extra money and get them ceramic coated. Choose not to - BIG mistake on our part. Headers are now starting to rust after one year of being on the car.
The following link will Jet-Hot coat any headers you send them regardless of condition. They will clean blast them them Jet-Hot coat them:
http://www.jet-hot.com/home.html