The Nissan Altima SR is a mid-size sedan that is part of the Altima line of vehicles produced by the Japanese automaker Nissan. It is available in both four-door and two-door body styles. The SR trim is the sport-oriented version of the Altima, and it features various enhancements, such as larger wheels and tires, more aggressive styling, and upgraded interior and exterior features. Available engine options include a standard 2.5-liter four-cylinder engine, as well as a 3.5-liter V6.