Striking the balance for DIY and enthusiast buyers

PaintNuts runs a leading automotive e-commerce platform—a true challenger brand. They make it easy for DIY and classic car owners to find precision color-match paint and repair solutions, fast. The challenge: the site attracts both high-intent users (fix-it-now buyers) and more hesitant, knowledge-seeking users. Designing a flow that supports both—guiding the uncertain, but not slowing down those who know what they want—was critical for increasing sales and user satisfaction.

Proving impact through risk-mitigated AB testing

Our hypothesis was that an improved damage selector could meaningfully boost conversions. Rather than implementing directly, we designed a robust AB test: 50% of users saw the standard category page, 50% the new version. When the first version missed the mark, crowding out confident buyers, we reviewed heatmaps and session replays to refine our approach. The next variant focused on subtle integration—helping those who needed guidance, without hindering high-intent shoppers.

Agile testing, deep analytics, smarter iteration

Door4 collaborated closely with PaintNuts, blending design refresh and user experience insights. We updated branding on an existing, underutilised selector tool, then embedded it above the fold. When early results flagged confusion—users mistaking options for filters—we pivoted rapidly. Our analysts drilled into qualitative and quantitative data, feeding improvements to design. The improved variant was launched promptly, ensuring both speed and controlled assessment of commercial impact.

Concrete, measurable improvement in conversions and revenue

Both Door4 and PaintNuts agreed that success would be measured by conversion rate uplift and average revenue per user (ARPU), benchmarked against a live control. The improved selector had to guide the uncertain, remain invisible to those ready to buy, and move bottom-line metrics. When the test delivered a +6.3% lift in conversions and +7.7% ARPU, the result was a tangible commercial win.

PaintNuts can now convert more buyers, with customer-centric UX and validated growth

PaintNuts now serves both hesitant and expert buyers efficiently, increasing the value of every visit. With robust testing and iterative CRO, they avoid costly missteps, safely rolling out enhancements only when proven to deliver. The approach sets a new, risk-mitigated standard for future optimisation and innovation. PaintNuts can now confidently continue CRO and UX evolution, knowing that customer insight, rapid testing, and commercial impact are driving every decision. The result is an experience that delivers measurable revenue growth, not just design tweaks.

PaintNuts is a UK market leader in the automotive aftermarket, specialising in precision colour-match paint for both modern and classic vehicles. Known for their unique registration lookup and historic paint code database, they serve both urgent modern car fixers and discerning classic enthusiasts. PaintNuts operates a high-volume e-commerce platform, handling buyers who require clear guidance and those who already trust the brand and know exactly what they need.

With conversion rates plateauing, PaintNuts needed a solution to capture more revenue from existing traffic, specifically by reducing friction for new or uncertain buyers on their main category page. The objective was clear: implement a scalable UX feature to drive incremental online sales, validated by hard data and minimising commercial risk.

The category page’s UX had to work for multiple buyer personas—guiding those who needed help, without disrupting high-intent, repeat buyers. The existing damage selector tool was dated and underused; meanwhile, untested changes could create new friction and actually damage conversion rates. The challenge was to find a solution that reliably improved commercial outcomes for all users.

Why Door4? Door4’s CRO expertise combines data-driven methodology and real-world commercial focus. Our role was to hypothesise, test, and validate improvements, using analytics and user behaviour—never assumptions. PaintNuts chose Door4 for our track record of translating insight into incremental profit, and for a collaborative process that put data at the heart of every decision.

Strategic Response: Our initial hypothesis was that a more visible, user-friendly damage selector could help hesitant shoppers find products more easily, therefore boosting sales. To manage risk, we deployed a 50/50 AB test comparing the existing page against a refreshed version with the selector above the fold.

Collaboration & Process: Working cross-functionally, Door4’s CRO analyst set the test hypotheses and partnered with PaintNuts’ internal team and our own designers to update the tool’s branding. After the first AB test indicated lower conversions—7% down for the variant—our analytics team scrutinised session recordings and heatmaps, uncovering that the design slowed down expert users and confused some by mimicking filter UX.

Execution: We pivoted quickly. The damage selector was reworked for subtlety and clarity, addressing the needs of different buyer mindsets uncovered during testing. The improved variant launched, and within two weeks posted a 6.3% increase in conversions and a 7.7% uplift in revenue per user—translating to a potential gain of tens of thousands of pounds per quarter at scale. PaintNuts avoided a costly misstep by not launching the initial, underperforming design.

Deploying the validated damage selector led to better guidance for decision-makers while preserving speed for decisive buyers. As a result, PaintNuts captured incremental sales from previously hesitant traffic, with no detriment to core conversion flows.

Quantifiable Performance Uplift: Key KPIs improved notably: conversion rates rose by 6.3%, and revenue per user was up 7.7% versus the control—delivering a pipeline of revenue growth worth tens of thousands quarterly when rolled out fully.

The process built a reusable CRO playbook tailored for PaintNuts’ buyer types, demonstrating that user-centred experiments can drive material commercial gains at low risk. The company is now set up to test, learn, and scale success across their customer journeys with minimal downside, a major shift from guesswork to evidence-based growth.