The 2015 Mustang is available as a fastback or a convertible with one of three engines. The base engine is a 3.7L V6, while the mid-level engine a 2.3L turbocharged 4-cylinder. More powerful Mustang GT variants are powered by a 5.0L V8. The V6 and 4-cylinder engines both make over 300 hp while the V8 engine makes well over 400 hp. In other words, the Mustang is fast in all of its forms. All engines can be mated to either a 6-speed automatic or a 6-speed manual transmission. There are five trim levels for the fastback: V6, Ecoboost, Ecoboost Premium, GT and GT Premium. The convertibles simplify things by only offering V6, Ecoboost Premium and GT Premium trims. V6 Mustangs offer 17-inch wheels, HID headlamps, power mirrors, a leather wrapped steering wheel, power windows and door locks, a 6-speaker stereo with Ford's SYNC system and a rear view camera. Ecoboost models come equipped with Ford's 2.3L 4-cylinder, which is more fuel efficient than the V6 while still making comparable power. Ecoboost models' standard equipment includes 18-inch wheels, a 6-way power adjustable driver's seat and a power adjustable passenger seat and an intelligent key. The Ecoboost Premium trim adds dual zone climate control, heated mirrors, additional exterior lighting and a 9-speaker stereo with SiriusXM satellite radio compatibility. The Mustang GT and GT Premium come similarly equipped to the Ecoboost trims, though of course GT models are powered by fire breathing V8 engines rather than fuel sipping 4-cylinder turbos.