Casey 1988
Shun the frumious Bandersnatch!
Some believe Star is a blend of Pro and Champion; I'm not totally sure of that, but it could be. Echostar was allegedly recycled Star, and may be the main ingredient of Swirly Star plastic (as an anecdotal observation, Echostar started going OOP as more Swirly Star molds were made for things like Tour Series). Chemists and Materials Engineers could probably talk all day about different blends and such stuff...
I guess one day we'll find out what I-blend really is.... opcorn:
Yep, Star is not quite a blend of Pro and Champion rather a more durable Pro as I have in last few years picked up a stiff Driver Pro disc that felt the way a softer run of Star plastic is. Star could be mostly Pro with a tad bit of Champion as little as needed to make a harder durable version of Pro.