Overall, the 2015 E320 L Sport 4MATIC has a solid reliability track record, making it a reassuring option for those looking to buy used cars in the luxury segment. However, potential areas to pay attention to include regular inspection of engine mounts, spark plugs, and suspension bushings—components that may need replacement with quality used car parts (if cost-effective) after long-term use, which can help manage maintenance cost over time. It is recommended to use Mercedes-Benz approved synthetic engine oil for routine maintenance and follow the official service intervals to preserve the car’s reliable performance. Since this specific vehicle has no recorded maintenance history, a professional pre-purchase inspection is strongly advised, a step many trusted used car dealers recommend, to check the condition of the 4MATIC all-wheel drive system and transmission fluid quality before committing to buy used car.