Wanted to have something to reduce the amount of air that passes through the underbody without lowering the car, and not have to worry about curbs and objects breaking it. Most front lips I've seen are made of fiberglass, carbon fiber, or abs. I recall seeing polyurethane lip, but even that is still not impervious to breakage imho.
Found a neoprene material used for sealing long gaps. It has a somewhat "L" shaped cross section, perfect for a simple, hard-to-break, lip. One side for the lip surface, one side to bolt on to the front bumper cover. Granted, it's not as thick as aftermarket lips out there, so it doesn't reduce the amount of underbody flow that much, but it's much more durable, and less expensive (read: less than US$15 total hardware) to replace. The black neoprene matches surprisingly well with the color & texture of the black oem pieces on the front bumper and sideskirt, even though none of them are neoprene.
If you're into
subtle (almost oem-like) looking lip that can reduce underbody flow without worries of it breaking, or costing too much, these photos may be interesting.
p.s. That tall pipe you see in the trunk area is a DIY tractor-semi trailer style muffler. Just kidding.