This from the KO web page comparing the EX-1 versions
Version 1
Original Version
Version 2
Master Unit has a software upgrade from Version 1 to Version 2.
Less twitchy around center for both steering and throttle.
5% faster response and more of a linear feel.
Version 3
Master Unit uses Version 2 software.
Includes newer “Expert Grip Unit”.
Trigger stroke and movement is different
Grip pad has a different fulcrum point and is in-between the original grip pad size and the large grip pad size.