I was thumbing through the latest copy of Sport and Compact car today. There are two articles in there about a company in Japan that built a couple of time attack cars (time trial cars). One is an S2000 and the other is an RSX. They did some pretty innovative (for the ricers) chassis stiffening on the cars. It is worth the price of an issue to pick it up. Will give you some good ideas for your next project.
I can't find a link on the web yet, so you will have to put the paper bag over your head and go to the book store to buy your own copy. (Wouldn't want anyone to know you are taking ideas from the ricers.)