I run a 20 series setup on a built Star in my Rupp. For the first two years it was both clone driver and driven. I did end up breaking one of the posts off the weight in the clone driver and just decided to upgrade to a comet driver and lighter weight at the same time and have no complaints. I am still running the clone driven, bent it, straightened it out and it’s never given me issues. I have always run a comet belt though, I actually just replaced my belt for the first time this year but still had plenty of life left on the old one