So because I want to go whole home backup, my main service panel can't be used to shunt all 200 amps to a GW2 and then in turn to a 200 amp distribution panel. The reason is my main service has a max 100 amp breaker requirement.
So the upgrade will remove the existing panel and install a meter with a 200 amp line to a new 200 amp distribution panel which will be my main service panel. All the lines coming into the existing panel will have to be relocated. Fortunately the location of the new panel is a shorter distance for all existing loads except for a single 15 amp line which will have to be extended.
They haven't told me who the contractor will be but just got the preconstruction proposal which is $4200. Seems pretty steep for a panel upgrade that requires no trenching nor does it require upgrading the service line.
$4200 seems in line with the industry. Keep in mind ALL the existing circuits need to be disconnected and removed, the main service may have to be moved. The job should require a new electrical inspection and permits. Then ALL the existing circuits need to be installed in the new panel along with your new Ckt breakers. Since this is a replacement job the electrical code may required mandatory upgrades for your service. It sound like you will be getting a new meter pan, this by itself is a big job. When you touch the meter pan the local utility most like will need to inspect and approve the new installation along with the local building department. So, I think your within the price range, plus California has a very tough electrical code. The California Code exceeds the National Code most of the time.