The standard engine is a 60-degree 4.0-liter SOHC V-6. It replaces the 3.8-liter 90-degree pushrod engine in the 2004 model. The 210-horsepower, 240 pound-feet engine – gains of 23 horsepower and 15 pound-feet over 2004 – is inherently smoother and more compact, providing more power and torque. They come with standard 16" wheels. An Exterior Sport Appearance Package is an option, and includes a rear spoiler and sport tape stripe on the lower rocker.

A T-5 five-speed manual transmission is standard, but for the first time, a five-speed automatic transmission is available.

V-6 Deluxe: Four-wheel power disc brakes, 4.0-liter SOHC V-6 engine, five-speed manual transmission, remote keyless entry, rear window defroster, stainless steel single exhaust, dual power side mirrors, 16-inch painted cast aluminum wheels, air conditioning, AM/FM stereo with single CD player, center console, front floor mats, door map pockets, cloth front bucket seats with 50/50 split rear bench (coupe), tilt steering wheel with speed control, power windows and door locks, front air bags and LATCH system child seat mounts in rear outboard seats.

V-6 Premium adds: 16-inch bright machined aluminum wheels with chrome spinner, Shaker 500 audio system with six-disc CD changer and MP3 capability, six-way power adjustable driver seat and leather seating surfaces.

Invariably some changes are made between the time preproduction cars are made and when the full production run is started. The 2005 Mustang was no exception. The major differences are that on the preproduction cars, the vertical bars in the lower front valence were painted to match the body, the 5-speed manual shifter was polished aluminum, and the pony medallion on the steering wheel was surrounded in silver on cars equipped with the Interior Upgrade Package.