Audi engineers put a lot of work into making the 2007 RS 4 more than a glitzed-up run-of-the-mill sedan. The primary ingredient is a 4.2-liter, dual overhead cam, 32-valve V8 engine pushing 420 horsepower at 7,800 rpm and 317 lb.-ft. of torque at 6,000 rpm, 90 percent of which is available between 2,250 and 7,000 rpm. This potent aluminum power plant uses a six-speed manual transmission to direct energy to each of the 19-inch alloy wheels and 255/35 Michelin Pilot Sport tires. The popular Audi S4 also houses a 4.2-liter V8, yet the RS 4’s version has been overhauled with all new internals; even the aluminum used to construct the block is different. The RS 4 also utilizes a tweaked exhaust system with two large oval outlets rather than the S4’s quad tips, and an S button on the instrument panel opens things up for a louder, deeper sound while also putting a quicker response behind the aluminum accelerator pedal. All told, the amped RS 4 pushes an additional 80 ponies and 15 lb.-ft. of twist when compared to the revered S4 and reaches 60 mph in 4.8 seconds instead of 5.3. The top speed is electronically limited to 155 mph, and maximum revving takes place at 8,250 rpm.

Using the brand’s quattro all-wheel-drive system with a Torsen center differential, the RS 4 usually functions with 60 percent of the output going to the rear wheels and 40 percent to the front, though 100 percent can be reapportioned to the front or rear as necessary. If only Audi’s engineers could better distribute the 3,957-lb. curb weight, calculated to be 58 percent carried in front and 52 percent in the rear. The 2007 Audi RS 4 sits 1.4 inches lower than the A4 and rides on a four-link front suspension with a double wishbone setup out back. Dynamic Ride Control employs a central reservoir joined to diagonally-connected dampers in an effort to limit pitch and roll.

Front and rear tracks have been widened, the 36.4-foot turning circle is more than a foot tighter than the S4’s, and the cross-drilled brake rotors are larger by 20 mm and 4 mm, front and rear, respectively. Functioning vents in the lower front fascia and liquid jets help to prevent brake fade, and automatic brake drying heightens stopping ability in wet conditions by causing slight, periodic contact between the pads and rotors. The braking system also features ABS and electronic brake-force distribution. Audi’s Electronic Stabilization Program (ESP) includes a two-stage defeat whereby one touch of the button on the instrument panel deactivates the traction control, while a second touch turns the system off completely – best to play with this mode on a track or in a big, empty parking lot, and make sure that all insurance policies are current. Steering is addressed by a rack-and-pinion system with Servotronic speed-sensitive assist.