You are in luck. One of the best shops in the state is just a few minutes away:
911design - Porsche service, maintenance and repair
Tell Loren you were sent by
The Boxster Brothers and he will take good care of you. He will be out at Fontana AAA Speedway all weekend doing track support for Porsche club racers. Come and watch them at work.
The bad news: No Porsche shops in SoCal work for $50/hr. Not honest ones anyways