[_delirium]

As always you should probably seek more authoritative advice, but my understanding is that you'd only pay CA corporate taxes, and not DE corporate taxes. Most states tax corporations on the business they do in the state, and it sounds like you do all your business in CA, so you have to pay CA taxes. But you don't have to pay DE taxes, because DE has a special exemption for DE-registered corporations that do all their business out of the state.