Resurrecting this thread...

Ok.. so wifey says "what do you want for Christmas"? And I'm thinking about Driving School at Thunderhill Raceway and a helmet. The thunderhill website isn't explicit (other than saying must be Snell approved). I need one helmet for:

- autocross
- karting
- track (Thunderhill, and Leguna Seca... if my dreams ever come true)

Are SA helmet legal for motorcycle usage?

Do I need to get an SA helmet or will M do?
Are there track restrictions on open/closed face?