The two-seat, mid-engined Porsche Boxster was available in three models for 2004. The base-model Boxster was equipped with a 2.7-liter horizontally opposed (or boxer-style) six-cylinder engine that produced 228 horsepower, while the Boxster S was powered by a 3.2-liter horizontal six-cylinder that generated 258 horspower. New for 2004 was the limited-edition Boxster S Anniversary Edition, which commemorated the 50th anniversary of the Porsche 550 Spyder, which influenced the design of the Boxster. It received a 3.2-liter horizontal six-cylinder that produced 264 horsepower. A five-speed manual overdrive transmission was standard on the base Boxster, while the Boxster S and Boxster S Anniversary Edition received a six-speed manual transmission as standard equipment. A five-speed automatic transmission, with a gate for manual shifting, was optional. Standard features for the Boxster included air conditioning, power windows, power door locks, dual front and side airbags, leather seats, power heated mirrors, a keyless entry system, a power-adjustable driver's seat, a leather-trimmed steering wheel, and an AM/FM stereo system with an in-dash CD player. The Boxster also came with a rear spoiler, four-wheel anti-lock brakes, and a power convertible top. One of the few upgrades for 2004 was the addition of a sports exhaust system to the list of options. Drivers thought the Boxster flew the Porsche flag well, even though it was the automaker's entry-level vehicle. They praised its quickness, handling, reliability, suspension, and even its stereo system. Though most Boxster drivers found little to complain about, some would have liked to have a little more legroom and storage space.