Some things are changing for autocross this, particularly with what cars go in what classes so I though I'd try and explain some of what's going on.
1: "STR" class. It's a new class for cars like the S2000, Miata, and various other 2 seat sports cars that never had a home when equipped with street tires. This class is for those cars with street tires of a treadwear rating of "140" or higher with various wheel width restrictions. This falls into the "Street Touring" category rules.
2: Stock classes changing, I personally don't have all the info but the main classes affected are "A,B,and C Stock. A lot of cars are being moved around in these classes. For instance the C5 vette(non-Z06) are moving to A-stock from Super Stock and such. The FD RX-7 is moving as well but who cares since there are no stock Rx-t's out there!!
Here is the link with the new rules: http://scca.org/contentpage.aspx?content=61 Torwards the bottom are PDF files with the rules and car classifications. I will try to awnser any questions people have.
If you have more questions or want to keep up with the local autocrossers on their forum go to http://forum.ovr-scca.org/ There are many veterans on there that can help and anything goin on with our region will be posted in there.
Ben