Vehicle Overview A high-performance S4 sedan and S4 Avant wagon rejoin the compact Audi lineup for 2004. Both pack a 4.2-liter V-8 engine that produces 340 horsepower. Audi advises that this is the first use of V-8 power in the segment. A six-speed-manual gearbox is standard, while a six-speed Tiptronic automatic transmission with paddle shifters may be installed. A Dynamic Shift Program in the automatic unit selects from more than 200 shift patterns to match the drivers style. Quattro all-wheel drive is standard. A Torsen torque-sensing center differential helps send power to the wheels with the most traction. The extensive use of aluminum in the suspension yields low unsprung mass, which improves ride comfort. Exterior The S4s double grille features unique S-model execution and is flanked by xenon high-intensity-discharge headlights with titanium-colored inner housings. Full body paint is used the bumpers are also painted. Large front air intakes are installed, and a side trunk-mounted spoiler appears at the rear. The mirrors are composed of aluminum, and AVUS cast-alloy wheels hold 18-inch tires. Interior Five people fit inside the S4 sedan and S4 Avant both feature a 60/40-split, folding rear seat. The driver faces gray instruments and a leather-wrapped three-spoke steering wheel Tiptronic shift paddles are installed on models equipped with the automatic transmission. Silk Nappa leather upholstery gives occupants a treat, and the Recaro ultra-sport seats have 12-way power adjustment. Standard equipment includes automatic climate control with a sun sensor, an Audi Symphony II 10-speaker audio system with an in-dash six-CD changer, remote keyless entry and an anti-theft alarm system. Interiors are trimmed with gray birch wood. All S4 models are prewired for either XM or Sirius Satellite Radio. Options include a navigation system, Motorola hands-free digital phone and 215-watt Bose premium sound system. Under the Hood Audis 4.2-liter V-8 engine, which is used in the automakers larger models, was modified to fit into the S4s compact compartment. Developing 340 hp at 7,000 rpm, the V-8 produces 302 pounds-feet of torque at 3,500 rpm. Audi claims the S4 can accelerate from zero to 60 mph in 5.3 seconds when equipped with the six-speed-manual gearbox. A specially tuned exhaust system is installed. A six-speed Tiptronic automatic transmission that features manual-shift capability is also available. Safety Antilock brakes have front and rear Electronic Differential Locks and electronic rear-brake pressure regulation, preventing the car from losing control during sudden stops. Standard Sideguard curtain-type airbags deploy from above the side windows and cover the entire side-window area. They stay inflated for about 5 seconds to provide head protection in rollovers. Seat-mounted side-impact airbags for front occupants are standard, and rear airbags are offered as an option. Height-adjustable front seat belts have load limiters. LATCH child-safety seat tethers are installed.