How to Choose a Remapper (Red Flags Included)

Every van says 'specialist'. Every website says 'custom'. Here's the working checklist for separating file writers from file resellers — qualifications, questions, paperwork and the red flags that should end the conversation.

You're trusting someone with the software that runs your engine. Choose well and the car is transformed with paperwork to prove it; choose badly and you've paid a stranger to flash an unknown file into a £30,000 machine — and the stranger can't even open the file to tell you what it did. (That's not an insult; it's how most of the industry is built.) Here's the checklist we'd give a family member.

Green flags: what good looks like

• They write their own files — and can prove it. The defining question of the entire industry. Ask who authors the calibration and whether that person can adjust it, on site, today. A master tuner answers in one sentence.
• Recognised qualification. The IMI accredits the only independently recognised remapping qualification in the UK. It certifies competence, not marketing budget. All APT technicians carry it.
• Diagnostics before quotation. A professional checks engine health before promising anything — because a remap amplifies whatever it finds.
• Measured results. Data-developed files with before/after figures logged from your engine, not a brochure percentage. Ask where their numbers come from; 'the portal' is an answer, just not a good one.
• Your original file archived and offered. A tuner confident in their work is happy to keep — and return to — stock. It's your software; treat anyone cagey about it accordingly.
• A guarantee with teeth. Ours is 30 days, money back, original file restored. Resellers structurally can't offer this: they'd be refunding a product they can't inspect.
• Longevity and a landline. Twenty years, fixed premises and a phone number that rings a human are boring credentials — right up until you need aftercare.

Red flags: end the conversation

• 'Same-day mobile remap, any make, any model, £149.' Universal coverage at panic pricing means template files from a portal. Your engine deserves more thought than a dropdown menu.
• Gains that ignore your engine. Anyone quoting '+40bhp' before asking your exact variant, mileage and history is reading a price list, not an engineering spec.
• 'No need to tell your insurance, it's undetectable.' One sentence containing bad law and bad engineering. Here's what non-disclosure actually risks.
• Warranty by WhatsApp. No premises, no paperwork, no VAT invoice — no accountability when the van's livery changes next spring.
• DPF/EGR delete offered casually for road use. It's an MOT failure and an offence on-road (full explanation here). A tuner relaxed about that law will be relaxed about the ones protecting your engine too.
• They can't explain their own file. Ask *what tables did you change and why*. Watch. A writer lights up; a reseller changes the subject to horsepower.

Price differences in remapping aren't margins on the same product. They're different products wearing the same word.

The paperwork you should drive away with

1. 01A VAT invoice naming the vehicle, the work and the stage.
2. 02Before/after power and torque figures (your insurer will ask for these).
3. 03Written confirmation your original file is archived and restorable.
4. 04The warranty terms — what's covered, for how long, in writing.

The five-minute filter

If you take one thing: ring them and ask 'who writes your files, and can I speak to them?' Everything else on this page is detail; that one question sorts the industry into its two real categories in under a minute. We're happy to be tested on it — call your local branch and ask for the person who'd be calibrating your car. Or start with the registration lookup and see the engine-specific numbers we're prepared to put our name to.