How to Insure a Car With Aftermarket Modifications

Insurance companies treat modified cars differently than stock vehicles

A modified car — one with aftermarket parts like a lifted suspension, custom engine work, upgraded wheels, or body kit — costs more to insure than the same model in standard form. Insurers see modifications as increasing either the replacement cost, the repair cost, or the likelihood of a claim. Some modifications also change how the car handles or performs, which affects risk.

The catch is that many people don't tell their insurer about modifications at all. If you file a claim and the insurer discovers undisclosed work, they can deny the claim or cancel your policy. The safer path is to disclose what you've done, get a quote that reflects it, and decide whether the added premium is worth keeping the modifications.

What you pay depends on what you modified, how much the work cost, whether the parts are bolt-on or permanent, and whether the modification increases performance or just appearance. A set of wheels and tires might add $20 to $50 per month. A turbo or supercharger can add $100 or more.

Key Takeaways

• You must tell your insurer about any aftermarket modifications before you have an accident, or they may deny your claim.
• Performance modifications (engine work, suspension tuning) typically cost more to insure than cosmetic ones (paint, decals, wheels).
• Some insurers specialize in modified cars and may offer better rates than your current company; others will not insure modified vehicles at all.
• The insurer needs documentation of what was installed, the cost of the work, and whether the parts are reversible or permanent.
• Modifications that increase the car's value or performance will raise your premium, but not disclosing them can result in a denied claim.

What counts as a modification your insurer needs to know about

Not every change to a car requires a call to your insurer. Routine maintenance — new brakes, oil changes, battery replacement — does not. But anything that changes the car's structure, performance, appearance in a way that affects its market value, or safety systems does.

Common modifications that insurers care about include: engine modifications (turbo, supercharger, ECU tune, displacement increase), suspension work (lowering, lifting, coilovers), wheels and tires (especially if they're larger than stock), body modifications (widebody kit, custom bumpers, hood vents), interior work (racing seats, custom dash), and safety additions (roll cage, racing harness). Paint jobs, decals, and vinyl wraps usually don't matter unless they're part of a larger visual overhaul that increases the car's value.

If you're unsure whether something counts, call your insurer and describe it. They'll tell you whether it needs to be added to your policy. It's a five-minute conversation that protects you later.

How to disclose modifications to your current insurer

Contact your agent or the insurer's customer service line and tell them you have modifications to report. Have the following information ready: a list of each modification, the date it was installed, the cost of the parts and labor, the name of the shop that did the work (if applicable), and photos or documentation if you have it.

The insurer will ask whether the modifications are reversible (can be removed and the car returned to stock) or permanent. They'll also ask whether any modifications affect the car's performance or just its appearance. Be honest — insurers can often tell the difference, and lying about it gives them grounds to deny a claim later.

After you report the modifications, the insurer will either approve them and adjust your premium, decline to cover the car, or ask for more information. If they decline, you'll need to find a different insurer. If they approve but the premium increase is steep, you can shop around — some insurers charge less for modified cars than others.

Finding an insurer that covers modified cars

Not all insurers will cover a modified car, and some have strict limits on what modifications they'll accept. Standard insurers like State Farm, Geico, and Allstate often decline heavily modified vehicles or charge premiums that make coverage impractical. Specialty insurers focus on modified, classic, or performance cars and may offer better rates.

Insurers that commonly cover modified cars include Hagerty (which specializes in classic and collector cars but also covers some modern modifications), Grundy, American Collectors Insurance, and some regional carriers. Performance-focused insurers like those affiliated with car clubs or enthusiast groups may also offer coverage. Your current insurer may have a performance or specialty division you can transfer to.

When you call a new insurer, lead with the modifications. Tell them exactly what you've done and ask whether they cover that type of car. If they say yes, ask for a quote. If they say no, move to the next one. This saves time and prevents you from going through an application only to be declined.

What documentation you'll need

Insurers want proof of what was done and what it cost. Gather receipts from the shop that performed the work, invoices showing parts and labor, photos of the installed modifications, and any warranty documentation. If you did the work yourself, keep receipts for the parts you bought and take photos showing the before and after.

For engine modifications, some insurers ask for a dyno sheet (a printout showing the car's horsepower and torque output after tuning). For suspension work, they may want the shop's documentation of what was installed. For body work, photos are usually enough. The more documentation you have, the easier it is for the insurer to assess the modification and quote you accurately.

If you don't have receipts — for example, if the work was done years ago — write down what you remember: the shop name, the approximate date, and what was installed. The insurer may still cover it, though they might ask you to get a mechanic's inspection to confirm the work was done professionally.

How modifications affect your premium and coverage limits

Your premium will increase based on the type and extent of the modifications. Performance modifications (engine work, suspension tuning) typically add more to your premium than cosmetic ones. A $500 set of wheels might add $15 to $30 per month. A $3,000 turbo installation might add $75 to $150 per month. The exact amount depends on your insurer, your location, your driving record, and the car's base value.

Some insurers will also adjust your coverage limits. If your modifications significantly increase the car's value, your collision and comprehensive coverage limits may need to increase to cover a total loss. For example, if your car was worth $20,000 stock but is now worth $28,000 with modifications, you should increase your collision limit to at least $28,000. Otherwise, if the car is totaled, the insurer will only pay out based on the stock value.

Ask your insurer whether they'll cover the cost of the modifications themselves in a claim, or only the car's base value. Some policies cover the full modified value; others cover only the stock value plus a set amount for aftermarket parts. This difference can cost you thousands in a total loss.

What happens if you don't disclose modifications

If you file a claim and the insurer discovers you have undisclosed modifications, they can deny the claim entirely. This applies even if the modification had nothing to do with the accident. For example, if you have a turbo but file a claim for a fender bender, the insurer can still deny it because you lied about the car's condition when you bought the policy.

In some cases, the insurer may cancel your policy outright, leaving you without coverage and potentially unable to find another insurer willing to take you on. You may also face a gap in coverage, which can complicate future claims and rate quotes.

The financial risk of non-disclosure far outweighs the cost of a higher premium. A $50 monthly increase is $600 per year. A denied claim on a $10,000 repair is $10,000 out of pocket. Disclose the modifications, pay the higher premium, and protect yourself.

Frequently Asked Questions

Will my insurance go up a lot if I add wheels and tires?

Wheels and tires alone usually add $15 to $50 per month, depending on how much larger they are than stock and whether they're high-performance tires. Larger wheels can also affect your car's handling and fuel economy, which some insurers factor in. Call your insurer with the wheel size and tire rating to get an exact quote.

Can I remove modifications before a claim to avoid the higher premium?

No. Your policy is based on the car's condition when you bought it. If you file a claim and the insurer inspects the car, they'll see whether modifications are present. Removing them after an accident looks like fraud. Disclose what you have, and keep it that way.

What if my insurer says they won't cover my modified car?

Shop for a different insurer. Call specialty insurers that focus on modified or performance cars. You can also contact your state's insurance commissioner's office for a list of insurers licensed in your state; some smaller carriers specialize in high-risk or modified vehicles. Be prepared to pay a higher premium, but you will find coverage.

Do I need to report modifications if I'm just keeping the car stock-looking?

If the modifications don't change the car's performance or value — for example, a paint job or decals — many insurers won't require you to report them. But if there's any doubt, call and ask. It's better to report something that doesn't matter than to skip something that does.

Will my insurance cover the cost of the modifications if the car is totaled?

Only if your policy specifically covers aftermarket parts. Some insurers include this automatically; others charge extra for it. Ask your insurer whether your collision coverage includes the full modified value or just the stock value. If it's just the stock value, ask about adding an endorsement for aftermarket parts coverage.