415 Petaluma Blvd N, Petaluma, CA 94952
Been going there since they started requiring "smog checks" on diesels.... Plus they are 4 blocks away from my shop. Very fast in and out times if they are not stacked up with customers. You could always walk a few blocks up and go to the military museum / surplus store if you have to kill some time and pick up a lightly de-milled MG-42 for giggles.