In case anyone did not get the e-mail regarding parking @ Laguna:

The option to leave your vehicles at Laguna Seca between the SFR Regional on Sept. 12-14 and the Runoffs in October has been confirmed by Laguna Seca management this week.
Vehicle Parking before Runoffs
Vehicles can be parked at Mazda Raceway Laguna Seca between September 14 and the Runoffs. They must be moved to the Purple Parking lot and there will be no charge. Those leaving a rig will need to sign a "Hold Harmless" release form that states MRLS is not responsible for any damage or theft.

Purple Parking is a dirt lot up above the racetrack.
See map: http://www.mazdaraceway.com/map-directions/track-maps-0