The 2015 Ford Mustang's slick styling will probably be the subject of numerous debates, but there's just as much going on underneath the sheetmetal.

For the Mustang's 50th year, the engine lineup will consist of a 5.0-liter V-8, a 3.7-liter V-6, and--for the first tine since 1993--a four-cylinder engine.

That four-banger is a new 2.3-liter turbocharged and direct-injected EcoBoost unit. It produces 305 horsepower and 300 pound-feet of torque, and will actually serve as the mid-range engine option in the Mustang lineup.

While Ford already has a family of turbocharged EcoBoost engines, this one has a new a low-inertia twin-scroll turbocharger--which the Blue Oval says quickens boost response--and a cylinder head with an integrated exhaust manifold, which has individual inlets for increased efficiency.

LEARN MORE: 2015 Ford Mustang Preview: Official Photos And Videos

A small four-cylinder engine may seem like sacrilege in America's most iconic muscle car, but there really is nothing new under the sun. Ford offered the four-cylinder Mustang SVO performance model from 1984 to 1986, and offered a 2.3-liter four until 1993. Since then, tuners and high fuel prices have made small, efficient engines much more popular.

Of course, the Mustang lineup will still be anchored by a V-8. It's an evolution of the 5.0-liter "Coyote" unit from the last Mustang, producing 420 hp and 390 lb-ft. Improvements include a new valvetrain and cylinder heads, as well as a new intake manifold with charge motion control valves. These valves adjust airflow at low speeds, improving the air-fuel mixture for better fuel economy, idle stability, and lower emissions.

Ford says many of the improvements to the V-8 are the result of lessons learned from the Mustang Boss 302.

Base models will get a carryover 3.7-liter V-6, with an estimated 300 hp and 270 lb-ft.

Also new to the all-new Mustang (aside from a brief stint with a retrofitted system on the Cobra in 1999-2004) is independent rear suspension. Using an H-arm, an aluminum knuckle, toe and camber links, and inboard springs, the new suspension isn't quite the A-arm geometry you might expect of a performance car, but it should offer a marked improvement to both ride quality and handling compared to the previous solid-axle setup.

A Getrag six-speed manual transmission is standard equipment on the 2015 Mustang; a six-speed automatic with paddle shifters is optional. Expect transmissions with more gears in the future.


Follow Motor Authority on Facebook, Twitter, and Google+.