During a drive along the Pacific Coast Highway through Malibu, Calif., last week, an early-’80s Porsche 911—clearly headed to or from the beach—zipped by. Clean and unadorned, the pre-’90s 911s are the essence of simplicity, without shiny trim, scoops, or spoilers to compromise their perfect profile. But this car, with a quintessentially West Coast Chiffon White paint job and black interior, did sport one very inapposite addition. Extending 6 feet from the sunroof and standing like a dictator in a state limous…