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Modified Car Insurance:
What You Need to Know
Complete guide to properly insuring your modified vehicle and protecting your investment.
📖 8 min read📅 Updated October 2025
Why Standard Insurance Isn't Enough
Most standard auto insurance policies don't cover aftermarket modifications. If your $50,000 built car with $20,000 in mods gets totaled, your insurance will typically only pay out the stock vehicle's market value— leaving you to absorb the entire modification cost.
Even worse, failing to disclose modifications can result in denied claims or policy cancellation when you need coverage most.
Types of Modified Car Insurance
1. Standard Policy + Endorsement
Add modification coverage to your existing policy
- Easiest option with current insurer
- Usually covers $5,000-$10,000 in mods
- Limited coverage amount
- May still depreciate modification value
2. Agreed Value Policy
Insurer agrees on specific vehicle value upfront
- No depreciation—agreed value paid if totaled
- Covers full modification value
- Best for high-value builds
- Higher premiums
- Requires professional appraisal
3. Specialty/Enthusiast Insurance
Insurers specializing in modified and performance vehicles
- Understands modification value
- Better claims process for modified cars
- Options for track day coverage
- May have mileage restrictions
- Not available in all states
Popular providers: Hagerty, Grundy, American Modern
What Modifications to Declare
Always declare these modifications to your insurer:
Must Declare:
- • Engine modifications (turbo, supercharger, engine swaps)
- • Suspension changes (lowering, coilovers, air ride)
- • Brake upgrades (big brake kits)
- • Wheel and tire changes (significant size differences)
- • Body kits and aero modifications
- • Performance exhaust systems
- • Custom paint or wraps
Usually Don't Need to Declare:
- • Interior accessories (floor mats, seat covers)
- • Small cosmetic changes (badges, emblems)
- • Phone mounts and electronics
- • Minor aesthetic touches
When in doubt, declare it. Better safe than sorry.
Cost Considerations
Modified car insurance costs vary based on several factors:
Type of Modifications
Performance mods (turbo, engine) increase premiums more than aesthetic changes (wheels, exhaust)
Total Modification Value
Expect 15-30% premium increase for $10k-$20k in mods, 30-50% for $20k+
Your Driving Record
Clean record helps offset modification premium increases
Usage Pattern
Limited mileage or pleasure-use policies can reduce costs
Documentation Requirements
To properly insure modifications, gather this documentation:
- 📄Receipts and Invoices: Proof of parts purchased and installation costs
- 📸Photos: Detailed images of all modifications
- 🔧Professional Installation Records: Shop invoices showing labor
- 📊Appraisal: Professional valuation for agreed value policies
- 📋Modification List: Detailed list with brands, models, costs
Common Insurance Mistakes
Not Declaring Modifications
This can void your entire policy, not just mod coverage
Assuming Coverage Without Asking
Always get written confirmation of what's covered
Lack of Documentation
Without receipts, insurers won't pay for modifications
Track Day Confusion
Standard policies don't cover track use—get separate coverage
Document Your Build on RoaringShifts
RoaringShifts helps you keep detailed records of all modifications, receipts, and photos—making insurance claims and valuations much easier. Build your modification history as you go.
Start Documenting Your Build