i don't recall where i read it, but i believe the difference between the two is one is more agressive, meaning i guess more snappier
i am having them installed on her ski, and asked for the one that is less snappier to be installed, guess you can less of a the on/off type of feel
i don't know what number is which as i dont have the kit in front of me
i am not 100% sure on this though