The Flex offers two advantages. Number one you can set the preload and length of the shock so that you can match the stroke perfectly to the ride height desired. Because of this there is no need for helper springs. Secondly, it allows you to use the EDFC if you want. EDFC will alter the shock damper settings automatically from inside the car. So you can leave them on soft for highway and stiffen them up at the touch of a button. Very slick. It has 3 memory positions and will tell you what settings you're on.