The 2011 rules are released, Link below:
2011 Cars and Rules SCCA page
Also, here's a quick guide for SCCA classing. Regardless of what you've done to your car, the focus will only fall into the classes listed below. I've added a few details that should give you a good place to start, then check out the rule to confirm your mods fit the class. You can always PM me if you have a specific classing question, or start a quick thread, I'm glad to help out.
Stock class, like it sounds, almost no mods. The top guys will run R-comps and pricey dampers though.
2000-2011 Focus, all (Including SVT) H stock
Street touring, basic bolt ons: springs, dampers, air intakes, exhausts, etc. Tires must be >140 treadwear rating.
2000-2011 Focus, all (Including SVT) ST
2000-2011 Focus, all (Including SVT) STX if
you've added an aftermarket Limited Slip Differential (LSD), providing modifications meet STX rules
Street Prepared, ST mods plus, add throttle body, intake manifolds, no emissions equipment, etc., and no wheel size restriction.
2002-2004 SVT focus, DSP
2000-2011 Focus (all others), FSP
Street Modified, if you added a turbo/supercharger, you're here. As long as you don't remove any interior beyond the rear seats/belts, this is as high as you'll go. Check out the rules.
2000-2011 Focus, SMF (note this class is supplimental, cars could revert back to SM)
Prepared, how fast you go is directly proportional to the size of your bank account. Not many restrictions here. Check out the rules.
2000-2011 Focus, EP
You must be lost or have way to much money, read the rule book before coming out :D
If I made any errors in the above let me know too, now get out and race!