Talk to your independent insurance agent about any modifications, whether they were made by you or already present when you bought the car. Sometimes modifications don’t affect the price but need to be detailed on your policy regardless.
If you don’t declare all modifications to your insurer and later need to make a claim, your policy possibly could be declared invalid. The insurer may refuse to pay out or give you a reduced rate.
If the cost of modifications is too high, shop around for a different insurance company – they all have a different way to calculate risk.