“xv” refers to the tune of the shock I think.
I think the Kashima CTD is basically the same as my Kashima Adaptive Logic BV, but with climb, trail, descend rather then 0,1,2,3.
It seems to work well, and is super sensitive at the beginning of the stroke, but it seems to blow through the last part of the travel, as I often find the O ring at the very, very end of the shock after a fast DH section of trail.
If I were you, I’d whack an RP23 CTD Kashima thingymajig on and see how you like it, and then get it custom tuned if needed (that’s what I plan to do anyway). I have heard amazing things about coil springs on fives though, although I’m not sure if the weight is worth it unless you’re doing a lot of DH.