Heres what I did. I went down to the truck parts place, and for $7.00 each I bought the good rubber semi flaps. I used cardboard to make a template, and cut out the flaps as needed for spring hangers ect. The I made mouting bracket, and hung them. Point of intrest for this are, make sure you either have clearence when backing up, incase you hit a curb or are off road, you dont want to tear them off, or chain them back.
I dont like those nice little sissy ones the dealer gives you. to designer for me. These are functional. and look good.