Just as Mustangs of years past, the 2010 model is available as a 4-passenger coupe or convertible, with a choice of V6 or V8 engines. The 210-horsepower, 4.0-liter V6 is carried over from last year, but all Mustang GT models now get the 315-horsepower, 4.6-liter V8 that was previously featured last year's special-edition Bullitt model. Both models now offer either a standard 5-speed manual or optional 5-speed automatic transmission. Joining the lineup later in the model year will be an all-new version of the Shelby GT500, a high-performance variant of the Mustang that will now offer 540 horsepower from its supercharged 5.4-liter V8 engine. As before, it will only be available with a heavy-duty Tremec 6-speed manual transmission--and as before the GT500 will be distinguished by its twin racing stripes running the length of the vehicle--but Ford promises a retuned suspension, improved steering feel and, for coupes, high-speed-rated Goodyear Eagle F1 Supercar tires to get more out of the tremendous engine. The sheetmetal of all the Mustang models is almost entirely new for 2010. The most noteworthy changes are up front, where all models now get a "powerdome" hood that bulges upward, a redesigned grille and front fenders, new headlamps that have a slimmer look, and more aggressively sculpted lower air intakes. In back the Mustang has a new taillamp design that follows a vertical theme, and includes with more sharply styled rear corners, a creased decklid and a larger badge. The taillamps are of a modern LED design but also bring back a nostalgic feature from the 1960s Mustangs: Turn signal lamps blink from the inside outward. The Mustang has been especially upgraded inside. The redesigned instrument panel is still upright and uncluttered, but it has a new two-tone look with matte-metallic and soft-touch matte-black materials--both upgraded in appearance and feel. Deep-dish gauges with bright chrome trim rings look even better than before, and a redesigned three-spoke steering wheel includes audio and cruise controls. The overall interior packaging of the Mustang changed little, which means that quarters are tight, but front occupants will fit comfortably into supportive bucket seats while smaller adults or children will fit acceptably in the back seat. A retuned suspension in the Mustang brings a greatly improved ride while also improving handling, and more sound insulation assures a quieter cabin. The latest safety features are now features in this affordable sport car. Electronic stability control is now standard across the Mustang line, as are anti-lock brakes and seat-mounted side airbags. Both the coupe and convertible are offered in base, Premium, GT and GT Premium models. GT trims add the V8 engine, larger wheels and tires, fog lamps and a stainless-steel exhaust. In both versions, the Premium trim adds a host of interior comforts and conveniences, such as leather upholstery, aluminum accents, a My Color interior ambient lighting system, Shaker 500 premium audio, Sirius Satellite Radio and Ford's Sync interface, which allows hands-free calling through Bluetooth cellphones and control of audio devices. The options list has been expanded and now includes dual-zone climate control, a navigation system, a rear video camera, HID headlamps and a large glass roof.