The BMW 5 SERIES (2003-07) 523I 4DR SALOON 2.5 M SPORT is a premium mid-size executive saloon, designed for comfortable longer journeys rather than city-car duties. Its four-door shape gives passengers space and a useful boot, while the M Sport trim adds a more purposeful look. In the UK used-car market, it sits among established alternatives such as the Mercedes-Benz E-Class and Audi A6. mycarcheck.com has seen 89 look-ups for this exact model, covering 34 distinct VINs, offering a useful snapshot rather than a complete market survey. Checks show an average private-sale valuation of £1,600 and average recorded mileage of 128,000 miles. The cars average around 5,000 miles annually and 5.5 previous keepers, so condition and history deserve close attention. It suits commuters, couples and families seeking comfort, space and a more engaging drive than mainstream saloons. The smooth petrol engine adds appeal, but checks matter given its mileage.