i am going to use a rubber truck bed mat and cut it in half to use on both sides.
But did you watch the YouTube vide on installing them? I think it was linked at the bottom of the page. The way they mount, they may help. Either way, they will still stop the big rooster tails and the spray that comes up and into the back of the bedI think he means in front of the rear tires, the mud that goes threw the frame & onto the engine, ect Good idea on the bed mat or plastic sled, it needs something for sure other than having to remove it to clean in there. I bet some stuff will still get in there.