On a 400ex if you run an aftermarket shock linkage you shouldn't run a sprocket guard it will hit the subframe from the additional up travel, I use the GT Thunder skid plate, works great and good ground clearance. The owners of GT Thunder recently passed away but if you go to their website you can still get many of their products from other suppliers. I believe you can still get the skid plates and they are cheap!
AWRCS #484 QXC Senior class - yeah i'm old but i can still ride!
2000 400ex , dg pipe , k&n , ac nerfs and front bumper , burgard +2+1 a-arms, armidillo rear skid , rock beadlocks all around , kenda klaw xc's front and rear , 450r front shocks , GT Thunder front and rear springs and xc link , tusk braided front brake lines and clamps , moose case saver , streamline steering stabilizer , renthal bars , much more to come!