The kit works well with yfz 450 shocks, but it is a good idea to get the lowering kit as well as the yfz 450 shocks are longer.
I use the kit on the sons bike and am happy with it.
The bonus with the kit is that it allows you to choose from a few different widths, and can be modified to run different camber angles, very useful for loose dirt riding.
If you are never going to need to change anything but your camber, then go with the +3 arms.