[Brillig]

At the risk of thread necrophilia, I would like to object to the previous comments re: Young Mr. Grace, as some of us on this side of the pond do indeed take note of things British and Humorous.
On a more aerodynamic note, ABS plastic is excellent for aero projects, easily cut with wood working grade tools, not brittle, and has excellent thermal properties. Quite suitable for 'baffles' of the sort being discussed, as well as air dams, and kamm-back. Heat treated will bend and if 'shocked' with cold/iced water will take a set.