Selling a modified car: what should you tell us?

If your car differs from its original specification, explain those changes in the initial enquiry. Wheels, suspension, a remap or a wrap can be easy to overlook when you have lived with them for years. A clear description helps our team assess the actual car, rather than relying on the standard specification associated with its registration.

Gladius Motors reviews enquiries personally. A modification does not guarantee a higher offer, and this guide is not a promise that we can buy every modified car. The useful starting point is to tell us what has changed, what evidence you have and what remains unknown.

Make a list of changes, not just a “modified” label

Separate factory-fitted options from later alterations where you know the difference. If work was done before you bought the car, say so rather than guessing who fitted it.

• Engine and software: remaps, tuning boxes, engine replacements, intake or turbo changes.
• Exhaust and emissions equipment: replacement exhaust sections and any known changes to the catalytic converter or diesel particulate filter.
• Wheels, brakes and suspension: wheel and tyre sizes, spacers, lowering springs, coilovers or upgraded brakes.
• Body and appearance: wraps, resprays, body kits, lighting or structural alterations.
• Cabin and equipment: replacement seats, audio systems, alarms or other added equipment.

For each change, include the brand or part description, approximate fitting date and mileage, installer and any receipt you hold. An ordinary like-for-like service replacement is different from a performance alteration; describe the work itself if you are unsure how to classify it.

Be precise about tuning and paperwork

“Stage 1” alone does not tell us what software is installed or which parts were changed. Name the tuning provider if known, say whether you have an invoice or written specification, and distinguish a documented power figure from a previous owner’s claim. Do not estimate output or describe a car as standard simply because the change is invisible.

Keep relevant fitting receipts, alignment reports and specifications ready. You do not need to post bank details, identity documents or an unredacted previous owner’s invoice in a public place. In the initial enquiry, summarise the relevant work and say which records are available.

Two examples of useful descriptions

These are illustrative examples, not customer stories:

• “Lowering springs fitted in June 2024 at around 62,000 miles. I have the fitting and alignment invoices. The original springs are included. There is a scraping noise over some speed bumps; I have not had it diagnosed.”
• “The previous owner said the engine was remapped. I do not know the provider or power figure and have no invoice. The engine warning light sometimes appears after starting. The wheels are aftermarket; the original set is not available.”

Both examples separate evidence from uncertainty. Include faults even if you think they are unrelated to the modification. Our damage and faults guide explains how to describe noises, warning messages and intermittent symptoms without inventing a diagnosis.

Build a modification record you can copy into the enquiry

For each alteration, write one short record using the same five headings. This makes it easier to distinguish what you can prove from what a previous owner told you:

1. Change: the part, software or alteration, including the brand or specification if known.
2. When and by whom: the fitting date or mileage and installer, or “before I owned the car” if that is all you know.
3. Evidence: the receipt, invoice, alignment sheet, software specification or other record you actually hold.
4. Current condition: any warning message, noise, leak, rubbing, uneven tyre wear or other symptom, including intermittent issues.
5. Included: original parts, spare wheels, controllers, locking-wheel key or accessories that will come with the car.

For example: “Aftermarket 18-inch wheels, make unknown; fitted before I bought the car. No purchase invoice. Front-left tyre rubs the arch on full lock. Original wheels are not included; locking-wheel key is present.” This is more useful than “alloys fitted” because it covers evidence, condition and what is included without guessing.

If several changes were installed together, you can group them under one invoice but still list each part. If a tuning claim cannot be verified, write that uncertainty plainly. Keep the summary in the condition, history or faults boxes of the initial enquiry and use the optional detail photo for the alteration that most needs to be seen.

Check registration details and roadworthiness

Some changes must be recorded on the V5C, including changes to colour, engine, engine capacity and fuel type. Structural changes have additional requirements. Check DVLA’s current vehicle-change guidance for the exact alteration; do not assume every modification follows the same process. Tell us if the paperwork does not match the car.

Be explicit about removed or altered emissions equipment. Government guidance says a missing DPF originally fitted to the vehicle causes an MOT failure, and using a vehicle modified so it no longer meets its designed emissions standards is an offence. Disclosing a change does not make it lawful for road use.

A current MOT is not a full mechanical assessment: the official MOT guide explains what is and is not checked. Do not drive a car you know or suspect is unsafe. Explain the concern and seek qualified advice rather than attempting a road test for photographs.

Photograph its current condition and agree what is included

Use current photographs showing the car as offered. Complete the seven labelled views: front, rear, left, right, odometer, front seats and rear seats. The optional eighth detail photo can show an alteration or fault; describe other changes in the enquiry too. See the photo checklist.

List any original wheels, parts, keys or accessories included in the sale, and flag anything pictured that is not included. Do not remove or replace parts after receiving an offer without telling the team: the offered price is guaranteed provided the car matches the initial enquiry description. There is no need to commission a return to standard solely to submit an enquiry.

What happens after your enquiry?

Our team reviews the details and sends a personal offer by text and email, not an instant automated valuation. The secure offer can be accepted or rejected online within four days. After acceptance, we call within 24 hours to book free nationwide collection at an agreed time or a forecourt appointment.

There are no admin or transaction fees. Payment is instant once the sale is agreed. Read how your offer works before deciding.

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