I use American National. I have my house & three cars insured with them. We have a stated value amount on the car. I had to get an appraisal. My 911 is insured as a specialty car and overall driving is supposed to be under 5,000 miles a year. If I go on a long vacation trip I just notify them and they don't really care how far I drive in two weeks. I am allowed to drive it to work on occasion, and if my daily driver is in the shop for repairs.
My 911 insurance cost $200 per year for full coverage. Back in 2007 a suicidal deer attacked me just outside of San Luis Obispo CA. The insurance company did not blink. They let me take it to the local Porsche specialist and he fixed it properly. Single stage paint and it was right back to the way it was before the dang deer. I was out the cost of the deductible. While it was in the paint shop I paid him extra to repaint the door mounter mirrors. They had several rock chips and that was fixed. The paint still looks great after 5 years.
I can can testify that driving through LA traffic at 5:00 PM with a broken windshield is no fun at all. In fact is sucked big time.