Raceline USA has Willow Springs the BIG TRACK for $100. I had opportunity to try them out last April 08, 2012 @ Buttonwillow Raceway. Absolutely spot on event.
Impressed me when there was red flag. Very swift to remove the car from the track. And allow rest of us to enjoy track without canceling the session. Which means pushing back all other sessions. Other track event organizers will cancel the entire session, just so they can end the event on schedule and go home on time.
See you guys at the event actually it is Saturday and Sunday. Saturday is Street of Willow and Sunday is Willow Springs the BIG TRACK.