maxxfish said:Pegasus Racing has a product that may work.
It's called Special Highly Abrasion Resistant Chassis Wear Strip. It's 1" wide and either 1/4, 1/2. or 3/4 inch thick, sold by the inch. They can also custom cut shapees in the same thicknesses. I have a feeling it's a material similar to cutting boards (it's pictured in white). Of course it means that your car is even lower, and that you have to drill holes, but that may be better than a cracked clam.
You should also be able to find Delrin (a strong, machineable plastic) in black.
I thought about mentioning that then I realised that the stuff is tougher than the Elise bodywork, plus it is thick(lowers ground clearance) so you can imagine where you'll hear the "craaack!".
somewhere higher up at a close to visible attachment point for the clam.( Sod's Law)