I've got one of these on a DR400
It's a couple of inches shorter than the PE arm being the same length as the steel DR arm
One has to modify the pivot end to fit with a couple of internal spacing tubes, as it's too narrow. Happiliy it's a piece of P*** to do but it needs to be exactly the correct amount added on each side as there's no room for error with the chain tensioner.. An engineer charged an hour to do it, That also gets rid of the known weakness of this arm.