The 2007 Audi RS4 comes in a 4-passenger sedan only and is based on the A4 platform, but with more aluminum parts and suspension to reduce weight in order to optimize the engine performance of its FSI 4.2-liter, 420-hp V8.  The RS4 comes with a 6-speed manual only.  The direct fuel injection improves engine power and overall fuel economy.  Quattro all-wheel drive splits torque 40/60 front and rear.  ABS brakes, traction control, stability control, daytime running lights, fog lights, and front-side airbags are all standard.  
The 2007 RS4 is well equipped, despite trying to cut down on weight.  A full array of power features, including 10-way power seats are included.  Cruise control, rear parking assist, heated seats, a sunroof, keyless entry, a ski bag, Recaro leather sport seats, a trip computer, audio controls on the steering wheel, and automatic climate control are a smattering of standard features.  Options include a navigation ssytem, heated rear seats, Bluetooth, and satellite radio.  Leather and carbon fiber trim add elegance inside, and fender flares, side skirts, and a rear spoiler give it an understated sportiness on the outside.