No such thing as CA approved exhaust LOL. And yes im from CALI SO I know the law. All that matters is that it has a spark arrestor and A LEGIT LABEL ON THE MUFFLER if you wana go by the book to ride in public land. In the dunes in CA MOST PEOPLE DUMP THE SPARK ARRESTOR NO BIG DEAL THERE.
BUT IN THE FOREST USFS TRAILS YOU WILL GET CHECKED.
Yoshimura has an official label on it. Even then I dont even think CA BLM or USFS WANA BE COPS look for such label. All they care is for a spark arrestor and not TOO LOUD.
BUT TO MAKE IT OFFICIAL. Make sure your aftermarket pipe has an OFFICIAL USFS APPROVED spark arrestor label on it. One day its gonna peel off too.