"The GT-R is the ultimate expression of the Mustang platform," says Hau Thai-Tang, 2005 Mustang chief nameplate engineer. "Mustang spans more of the market than almost any other car – from an under-$20,000 V-6 to a race-ready car in the $40,000 range. The Mustang GT-R shows how we can expand that unmatched reach with the all-new platform."

Track time – at drag strips and on road courses – was a critical part of the 2005 Mustang’s development, as chassis engineers pushed prototypes to the limit in search of the perfect power-and-handling blend.

"We spent countless hours refining this car on development drives and at the track," says Mark Rushbrook, 2005 Mustang vehicle development manager. "The car has been to the Nelson Ledges road course in Ohio several times for 24-hour runs and has spent months on Ford's straightaways and handling courses at our proving grounds in Arizona, Michigan and Florida."

Soon after the 2005 Mustang’s world reveal in January, race engineers quickly began building on its solid foundation. The Mustang GT-R concept's chassis was fully stripped down to the body shell to receive custom reinforcement and structural improvements for driver safety on the racetrack. A roll cage was added, along with a Sparco-brand racing seat with a five-point safety harness.

The production suspension geometry is retained, but key parts were replaced to reduce weight or provide additional strength for the rigors of racing. Suspension pieces, including the K-member, are made of lightweight chrome-moly tubing. The race-proven dampers are coil-over, fully adjustable units featuring remote reservoirs. A strut tower brace increases structural rigidity.

Rounding out the chassis package are huge, race-proven Brembo brakes. The front features 14.3-inch rotors with six-piston calipers; the rear has 13-inch rotors with four-piston calipers. Linking the whole package to the racetrack are 20-inch wheels and racing slicks provided by Pirelli. Tire sizes range from 275/35 in front to 305/30 in the rear.

The Mustang GT-R is engineered with modern aerodynamics principles, including a massive front airflow opening and carbon-fiber belly pans that reduce underbody air turbulence.