Back on the insurance issue, your SCCA membership includes, I believe $2M in liability insurance in case you have a serious mishap. This won't pay for repairs to your car, but it would pay for your liability to another person.
This is one very good reason to pay for a membership every year.
Not sure how ER or S2K handle this, if at all.
S.
EDIT: I stand somewhat corrected:
All SCCA members are protected with the best event-related insurance program in motorsports at no additional cost. Properly registered SCCA members who are accidentally injured while participating at SCCA events are covered for up to $1 million in medical expenses. SCCA members, in certain circumstances, are also provided with limited third-party liability insurance coverage at most events. Contact the SCCA Risk Management Department at the national office for details.