We have an enphase system with a solar array that's a bit under 10x that size. We paid about $60k (ignoring tax credit) in the bay area, and I think we overpaid.

We have about 2.5 watt hours of battery per watt of solar panel, which seems about right around here. (The battery is fully charged by the end of day about 95% of the time.)

Your quote has 6.6 Wh/W, and the PV bit is small, so fixed costs are also biting you.

Edit: we have electric heat, and you probably don't. Our worst case days are cold and cloudy, so perhaps the battery sizing makes sense, though if you want AC at night, you'll want enough solar panels to charge the battery and run the AC.