My 911 is covered by my same insurance company that insures my other cars and the house.
The 911 has a stated value specialty policy and I can "only" drive it 5,000 miles per year. I can use it to commute if the El Camino is in the shop. I have high coverage for liability and free towing. The 911 is $11 bucks per month. I had to raise the valuation this year because the 911 is going up in price so much. That is a great problem to have, my toy is worth more every month.
The insurance company is American National. They even send me a check at the end of a year if I don't file a claim for three years.