Stated Value vs Guaranteed Value
Hagerty explains the difference between agreed vs stated value.
Agreed Value is more expensive to insure, because they will pay out whatever you insured the car for.
Stated Value is cheaper, typically used on more expensive cars to provide some protection. You could insure the car for 60k, buy if the market says its worth 30k, thats all you get.
Just get Accessory Coverage on your standard policy. 3000 bucks is like 8 bucks a month with most company, and the value of your accessories is covered at replacement cost.