"“at what cost to the identity of Porsche Club of America San Diego Region as a club for Porsche owners only, am I willing to go by allowing X cars and X drivers into our club and events?”
And I have always told people we are not an elitist club..

back to the drawing board.
First , nobody should have to be 'thankful' because its a privilege after paying their money and working the event as well. Dont confuse this with Appreciative , and appreciation for the work the volunteers put in, we all have great appreciation and respect in that regard.
What I dont understand as well, is in one statement you complain that there is an instructor burden for X cars then in the next breath you remove X car instructors..

Sorry, but this makes no sense IMHO.
Sorry, but allowing other marques in to run at ax events doesn't affect our identity, Being an Elitist club does however. As you have seen posted many times, I , as well as others , enjoy the opportunity to run against other marques.
I agree with PCA members getting instructors first , but lets manage it so you dont surprise x cars and send them home, or have the bad attitude of 'tough luck'.