It's tricky down here as there is no concentration of knowledge or service center, so the expertise is a little spread out. But DeBritton Aviation in Chino has quite a bit of Turbo Commander experience. Ariana Aviation in Chino also has some, but less (they take care of my aircraft now). For pistons, Security Aviation at HHR has some experience and owner is a DER and a good guy. And in San Diego, San Diego Jet Management and Gibbs have some Commander experience.