I think your current car is just fine to begin autocrossing. I wouldn't worry too much about being competitive at your first several autocrosses, especially in the Atlanta Region.

The poster above is correct a 240SX did win the national title in STS. However, STS rules allow some modifications that the stock classes don't. Your car is in G-Stock, assuming that it isn't modified beyond the scope of the stock class rules (i.e. stock classing allows a cat-back, replacement struts/shocks, and DOT R-comp tires). That puts you in the same class as the new Mini Cooper S. They pretty much dominate that class.

Autocrossing is a lot of fun, and will teach you a lot about car control. Those are the two most important things to focus on regarding autocross. Learn the basics first, then worry about being competitive.


Another thing to point out, is that a RWD car takes a different technique than a FWD car. Both have thier advantages and disadvantages, though.

Here's a link to the SCCA's web page with all the information about the current rules. And, another to SoloAtlanta's web site.