Hi, Shift works fine on these kites, in the Shift manual there is a setup guide with line lengths for Boxer, V4 and X4 kites. I have used it on Boxers from 9 - 16, V4 16, 20 and 25 and X4 8 and 12. You will have the benefits on all these kites, for sure it improves depower on the V4, it makes it rea...