Replacing the Challenger Electrical Panel for Townhome community [TH][CA][150]

Our community has around 150 townhomes built in the 90s in California. Recently our insurance company is refusing to cover our community if we don’t replace our old Challenger Electric Panels and our insurance is also set to increase.

Got a few quotes from some companies for 6k - 7k for replacing 2 panels per house. Looking for some guidance and experiences on how to accomplish this project. Whether a special assessment is required or do we ask homeowners to install the panels independently and just inspect the completion. What about permits from city and PG&E?

Would appreciate any inputs from HOA’s that have completed this project. TIA