San Diego and Southern California are a much bigger market than Northeast Oklahoma. I'm lucky to find more than two running 986s within 100 miles of my area. Here's a quick look at some searches that take only a minute or two. Pick a color:
It looks like Craigslist is still active for selling cars in the San Diego area.
https://sandiego.craigslist.org/search/cta?auto_make_model=porsche%20boxster&max_auto_year=2009&min_auto_year=1997#search=1~gallery~0~34
Facebook Marketplace is awkward to search and terrible to use, but in my area, it's where the for sale by owner cars are.
https://www.facebook.com/marketplace/sandiego/search?query=boxster%20porsche
Used car dealers like to feed their inventory to places like Autotrader:
https://www.autotrader.com/cars-for-sale/all-cars/porsche/boxster/san-diego-ca-92107?0=vehicledetails.xhtml&listingId=673051436&requestId=BOXSTE&searchRadius=100&marketExtension=off&startYear=1997&endYear=2004&isNewSearch=true&showAccelerateBanner=false&sortBy=relevance&numRecords=25
I think Ive bought over 20 now. Never had yellow and not sure if Rick (Redtele58) has a yellow one either. Next time I get rid of a black one, I should do a fly-n-drive to San Diego to get a yellow one.