[oil pan 4]

I remember reading a thread on a wrx form. It talked about a lawn edging air dam. The consensus was that the $14 for 20ft plastic air dam looked as good if not better than the $250 aftermarket one being sold. The only person that said it looked like trash was the forum shrill pushing the $250 one.
Also there is no 1 size fits all. Some vehicles you can just toss a bit of lawn edging up under and you're good. Others have uneven surfaces that need structure added to bridge the gaps. Other vehicles a 4 inch bit of black lawn edging won't do anything because the vehicle is so high up off the ground.