If you want to change alignment for autocrossing, you can easily get 1.5* neg camber in the front and if lucky get 1.1* in the rear. This will give you a good baseline and still street drivable. As to toe in/out, you should keep the stock settings.
When I was running stock GY's, I autocrossed them at 40/36. A word of caution. When you have the alignment changed take the time to torque all the bolts yourself when you get home. Myself and three others that I know of had problems with rear wheel toe in (extreme) after very aggressive autocrossing. You can ruin a good set of tires in just 400 miles (or 50 runs at an autocross).
If you are really serious about getting a good autocross alignment, then you should also cross weigh the car during the alignment process.