The Audi A4 features a 2.0L 4-cylinder turbocharged engine making 220 horsepower, which is connected to one of three transmissions: a multitronic continuously variable transmission (CVT) with front wheel drive, a 6-speed manual with quattro all-wheel drive, or a 6-speed automatic with quattro all-wheel drive. The truly impressive aspect of the 2.0L engine is its 258 ft-lb of torque, which Audi claims allows for 0-60 mph times in the mid-6.0-second range. The S4 shares the A4's refresh outside and still carries impressive performance under the hood. It features a 3.0L supercharged V6 that makes 333 horsepower and 325 ft-lb of torque. A choice between a 6-speed manual or 7-speed dual-clutch automatic transmission puts that power to the wheels. All S4 models come with quattro all-wheel drive only. Audi claims a 5.0 second 0-60 mph time and the EPA estimates up to 28 mpg highway with the automatic. The A4 is available in Premium, Premium Plus and Prestige trim levels, each with the buyer's choice of drivetrains. While Premium trim may be the most basic spec for the A4, its name is an apt descriptor of what Audi offers as standard on the car. Leather seating, 8-way power adjustable front seats, a sunroof, 3-zone climate control, automatic headlights with washers, and automatic windshield wipers are all standard, as is an excellent 10-speaker stereo. Other standard features include 17-inch wheels, fog lamps, dual exhaust, heated windshield nozzles and a multifunction steering wheel. The Premium Plus trim level adds a few niceties to the A4, including heated front seats, Bluetooth connectivity, 18-inch wheels, an integrated garage door opener, Xenon headlights, LED taillights, exterior aluminum trim and rear fog lights. Prestige level A4s include a navigation system, a 14-speaker, 505-watt audio system, keyless start/stop and entry, parking assist, a rear-view camera and a blind spot warning system. Prestige models include Audi Connect, an Internet-based infotainment system operating on the navigation screen. Options are also plentiful on the A4. There are three different types of wood veneers available, several different wheel styles, a sport package, a driver assistance package and an S-Line package. The driver assistance package includes adaptive cruise control, adjustable suspension and dynamic steering, giving drivers several different chassis setups which can be adjusted on the fly. The S-Line package also increases the sporting pretensions of the A4, with a stiffer suspension setup, sportier seats, 19-inch wheels and unique front and rear bumpers. A rear window shade and extra airbags are also optional. The S4 is available in Premium Plus and Prestige trims. An optional navigation package adds not only Audi MMI navigation but also a Bluetooth audio system, SiriusXM traffic, Audi Parking System Plus and a rearview camera. 18-inch 5-parallel spoke star design wheels are standard, while 19-inch wheels are available. The Prestige makes the navigation package standard. Safety in both the A4 and S4 is enhanced by anti-lock brakes, traction control, stability control and electronic brake-assist. Dual-stage front airbags are assisted by head curtain airbags and thorax side airbags. A tire pressure monitoring system is standard.