....a while back a few of us ran a vintage Mustang body only race at So Cal Raceway. Ran the tires/wheels, inserts with Paragon and they worked pretty good. The key is that they are good if everyone else is running them, ie. spec class, or if it's a very low bite track where everyone is struggling with grip anyway.
....they work, but keep in mind that they were not designed to go up against full fledged super sticky race tires.
