Autocross is all about getting around the cones, so maybe you want a larger rear brake. There is a rear brake re-size that is a simple swap.
Yup, I'm a Viper guy, but the cars share the same rear caliper. And yup, in AX, the first model year Vipers suck until they get better rear brakes.
40mmBrakes Home
I wrote the SELOC TechWiki articles about the brakes history and also how to rebuild them, so if you have any questions, let me know.