30+/day is more in line with my expectations and what I had heard. 50,000/year would not be much of a stretch at all, though they would need to add a second shift or spend money on the +4 hour overtime rate for California. That would increase capacity by ~50% and can be done immediately, though I would only want to do that on an interim basis to give me flexibility on building out a second shift.
I wouldn't expect the production rate to be increased in the first or second year. They need to prove to themselves they can sustain 20,000 cars first before investing in an increase. If they hit the 20k per year for a couple years and still have a large backlog, it'll be increased.