Thanks, I'll look into it. Unfortunately, alumalite isn't cheap or easy to find around me.
I've thought about building a sliding lower section in a two piece construction that when slid forward would allow for a larger splitter on the track, while when slid back would tuck away for ground clearance/safety on the street. I'd also plan NACA ducts for cooling the diff, transmission, and oil pan. I might also try to design NACA ducts to feed air to the brakes that the splitter would cover when slid back for street use.