I believe the racing team that made them was 3R's. They were very successful racing Corvette's, but then switched to Vipers a few years ago with even greater success. Anyway, I don't have a direct contact, but Gary Hoffman with Hardbar (www.hardbar.net) or Lou with LG should be able to forward...
I believe most commercial GM trucks use composite springs too. About the only things I can add is that the spring use unidirectional fibers, and there's a popular aftermarket spring company that's starting to make replacement springs....Eibach I think, which would make them the second...
Out of curiosity, why are you reverse engineering the upright? I know there was one group that has already done it, however I believe all their products raise the hub by 1 inch or more.
Isn't Tyvek what Fedex uses for their fabric envelopes? I believe they call them LargePak's. Super lightweight backpacking freaks use this material for groundclothes and other applications as you can see here...
It matters what market you're going for. In the auto industry there's a big market for bling-bling kits, but there's also a market (albeit smaller) for functional racing oriented parts. The problem with the racers is that many of them will require you to prove yourself and your products on the...