Buying out of states and bringing the car into California

So. I bought My Redeye from Jake at Cummins (not in person) in December. I thought they were handling all of the California DMV paperwork and kept waiting for my plates. My Kentucky temporary plates expired 2-17. I recently found out the car, even though brand new, had to be smogged, verified, and some additional paperwork filled out. Turns out all Cummins did was send in the money. Finally got to the DMV today and registered the car. There were $940 in penalties. Turns out cars must be registered within 20 days of bringing the car into the state. It would have been nice if Cummins would have told me, but they probably are not knowledgeable of the requirements in all 50 states. My fault, I guess. Anyone in California, learn from this.