Developed between February and November 2002, two pre-production concept cars, a convertible and coupe model, were presented by Ford at the 2003 North American International Auto Show on January 5, 2003.

[4][5][6] The Redline Red Metallic Ford Mustang GT convertible concept included a "showbar" with a rim of billet-aluminum trim, 20-inch wheels, 13.8-in cross-drilled Brembo brakes, red and charcoal leather upholstery with perforated surfaces on the seat backs, billet-aluminum shifter for the 5-speed automatic transmission, as well as 4-point racing-style seatbelts and instrument gauges.

[7] The Tungsten Silver Ford Mustang GT coupe concept included a glass roof and functional hood scoops, as well as a red and charcoal leather interior accented by billet-aluminum hardware and a supercharged MOD 4.6 L engine rated at 400 hp (298 kW; 406 PS).

At the following year's North American International Auto Show, Ford introduced a redesigned Mustang previewed by the 2003 concept vehicle that was codenamed "S-197".

The 2005–2009 base Mustang was powered by Ford's cast-iron block 4.0 L Cologne SOHC V6 engine, replacing the 3.8 L Essex OHV V6 used in 2004 and older models.

In spite of this, Ford has drawn heavy criticism from the automotive journalism community for the decision to equip the fifth generation Mustang with the live axle system.

Some of the options available included Ford's MyColor (a color-configurable instrument cluster available as part of the Interior Upgrade package), brushed aluminum panels (also part of the Interior Upgrade Package), Ford's Shaker 500 (500 watt peak output) or Shaker 1000 (1000 watt peak output) premium audio system with a 6-disc MP3-compatible CD changer, leather seating surfaces, a six-way power adjustable driver seat, and a four-channel anti-lock brake system with traction control (standard on GT models).

Replacement links from Ford are colored black or oxide coated [18] For 2006, a less expensive version of the Mustang was introduced as the new base model.

All Mustangs for the 2008 model year have seats containing material derived from soy beans,[19] harking back to some of Henry Ford's ideals.

Several new options and standard features were introduced in the following years, including the Pony Package (2006), a DVD-based GPS navigation system made by Pioneer (2007), a power passenger seat (2007), heated seats (2007), Sirius Satellite Radio (2007), new flat bottom spoiler for V6 only (2006), standard side airbags (2006), HID headlamps (2008), and ambient interior lighting (2006).

This option (US$1,995 at introduction) was in effect a full roof sunroof that splits the difference in price and purpose of the coupe and convertible models.

[22][failed verification] Available in 2008 as a $2,398 option, it was promoted with an additional Power Pack FR1 (an 85 mm Cold Air Intake sourced from the Bullitt, True Dual exhaust with an X-pipe and Bullitt Mufflers, a Pro-Cal Hand held tuner and a Ford Racing Performance oil filter), handling package FR3 (shocks/struts, front and rear anti-rollbars, V6 lowering springs, and a V6 strut tower bar) and a short throw shifter.

The V8 engine in these models had a power output of 319 hp (238 kW) by means of a Ford Racing air intake, performance tune, and upgraded exhaust system.

The GT-H also includes the handling package with lowering springs, improved dampers, sway bars, a strut tower brace and a 3.55:1 ratio rear axle assembly.

Available in Dark Highland Green or Black exterior paint without spoiler and GT fender emblems; the faux gas cap on the deck lid is replaced by a unique Bullitt version.

It has a cold air intake, improved engine calibration, and a revised exhaust system designed to mimic the sound of the Mustang used in the Bullitt movie.

It retained the same basic live axle rear suspension setup of the Mustang V6 and GT, with minor durability enhancements such as thicker sheet metal supports and extra welds, as well as redesigned strut towers to accommodate a wider engine.

The package featured a standard 3.31:1 rear axle, stiffer suspension tuning, 19-inch wheels with performance tires, a strut tower brace, and performance-oriented electronic stability control calibration.

[55] Other, non-powertrain related upgrades made to the 2011 Mustang included a Nexteer Automotive Electric Power Steering (EPS) system with pull-drift compensation and active nibble control, general aerodynamic and NVH improvements over the 2010 Mustang, a digital message/information center, blind spot mirrors integrated into the car's side mirrors, a universal garage door opener, a 160 mph speedometer, and Ford's MyKey programmable vehicle key technology.

Models equipped with the Pony Package offered LED lighting mounted on the side-view mirrors that produce a projection of a running horse on the ground, 18-inch wheels, and lower valance fog lamps.

All models equipped with the 6-speed automatic transmission included a SelectShift feature, which provided drivers the ability to choose and hold a gear and to shift manually.

Other, new features exclusive to the 2011 Mustang GT included "5.0" fender badges replacing the "GT" badges used previously, an optional Brembo Brake Package includes 14 inch Brembo front disk brakes taken from the Shelby GT500, unique 19-inch wheels with Pirelli P-Zero ultra high performance summer only tires, a unique calibration of the Advanced Track stability system including a "sport" mode, and suspension enhancements such as stiffer springs (less aggressive than the BOSS 302 and Shelby models but more so than the regular GT models) and various other suspension enhancements.

The car is white with red and blue accents and features USAF markings and logos, wide body modifications, a handcrafted and painted belly pan by Creations n' Chrome that emulated the appearance of an F-16 Thunderbird, front and rear wide body elements by TS Designs, custom 22-inch wheels by Forgiato, a modified navigation screen, instrument cluster, rear seat delete, Recaro seats with embroidered Thunderbirds elements, unique sill plates and puddle lamps, a Ford Racing supercharger, suspension handling pack and Brembo brakes.

The Boss 302 takes the Mustang GT's suspension and adds higher-rate coil springs, stiffer bushings, and a larger diameter rear stabilizer bar.

The Laguna Seca model loses its rear seats, which are replaced by a cross-car X-brace to increase structural rigidity approximately 10%.

[68] [69] The 2010 Shelby GT500 was revealed by Ford through a press release on January 1, 2009, prior to a public unveiling at the 2009 North American International Auto Show.

Various aerodynamic upgrades, such as the design of the front fascia and the aforementioned Gurney Flap spoiler, contribute to increased downward force and a reduced coefficient of drag.

Thanks to the new liner coating, which has friction-reducing characteristics, and a revised exhaust, horsepower production from the 5.4 L V8 has increased slightly for a total of 550 bhp (410 kW) at 6200 rpm.

The combination of the lighter engine, EPAS, and aerodynamic enhancements result in an improvement in fuel efficiency for the 2011 GT500 relative to the 2010 model that eliminates the car's gas guzzler tax.

Larger Brembo front disc brakes with six-piston calipers, reinforced axle tubes, and aero tweaks to help the car reach 200+mph safely.