Racechip.co.uk appears to be a legitimate website based on customer reviews. The site has a Trustpilot rating of 4.1 out of 5 with 77% of reviews being 5-star. Customers have praised the product quality, customer service, and performance improvements. However, there are some negative reviews mentioning installation difficulties and performance issues. Overall, the majority of feedback is positive, indicating that Racechip.co.uk is a trustworthy site for purchasing tuning products.