I agree with eldrm. The Scotts unit is very easy to install and holds up very well to rough riding. I race a few enduros in the Texas circuit and I have had 0 problems with all of my Scott's parts. They cost a little, but you definitely get what you pay for (IMO)!
Ok, so the Scott's unit is great. I also see on reader's rides pictures where several bikes have PCV disc guard. What's the scoop on that one and where can a person buy one? I can't find any links for PCV.
JCV220 is a reader and contributor to these forums who owns a machine shop (JCV Products) and he built a few of these guards for friends but his machine shop business has taken off to the point that he just doenst have time to make the one-off KDX stuff anymore.