Some may wonder what the difference is between the Audi S4 and the Audi RS 4, and how can anyone discern one from the other? There are several design cues separating the two, some more apparent than others. Among the more obvious examples are the flared wheels wells (sculpted into the body work and not simply tacked-on parts), gorgeous 19-inch alloy wheels, dual oval exhaust pipes in place of the S4’s smaller quad tips, the hunched-down stance, and RS 4 badges on the trunk lid, rear door moldings, and upper grille. The front fenders and hood are constructed of lightweight aluminum, and a subtle spoiler has been incorporated into the rear body design. Overall, the doors and roof panel are the only exterior panels shared between the RS 4 and other A4 models. Collectively, these enhancements transform this car into one mean looking German sedan, one that looks intimidating in the rearview mirror and track-ready from behind. And after chasing a few at hyperactive speeds through twisty canyons, it’s fair to say that even in yellow, there’s tremendous joy in watching this Audi do its thing.

Designers also performed a few tweaks to the RS 4’s interior by adding silver piping to the leather seats; stitching perforated leather to the steering wheel, shift knob, and emergency brake handle; and placing carbon-fiber trim around the shifter, on the doors, and along the dash. A high-quality mesh headliner matches the grain used on the A-pillar, which runs continuously almost to the B-pillar so there’s no ugly seam for the driver to look at. Everything inside of the 2007 Audi RS 4 is first-rate, from the soft leather to the padded plastics used on the dash, door panels and the cushioned armrests. The front bucket seats, made by Recaro, have bolsters that would stifle the movement of a sugar-fed kid on Halloween, with plenty of power adjustments, a manual pull-out section that lengthens the bottom cushion, multiple heat settings, and beefy headrests. The only downside is the hard center console that rubs uncomfortably against the driver’s knee in aggressive turns. A manual tilt and telescoping steering wheel provides a wide range of adjustment.

Rear seat passengers are afforded less respect, as evidenced by the tight knee and foot accommodations. Head room is plentiful, and three adjustable headrests are provided. But hard front seatbacks beat up passengers’ knees and getting lower extremities into the footwell is darn near impossible. A fold-down center armrest includes two retractable cupholders, a first-aid kit, and opens the way for a ski bag to be extended into the cabin.