I'm the happy owner of a second hand 2004 Ace Race disc. I had no idea what it was or whether it was any good when I bought it from the 2nd hand bin at PIAS. It turned out to be a Z Glide and glide it does. It has earned a place in my bag. The Z Glide is PDGA approved, but at the time of manufacture Ace Race discs are not. Are Ace Race discs which are subsequently approved by PDGA for tournament play grandfathered under the approval? Does anyone know or should I have to check with the TD at each tournament?