Like most Audis, the RS4 isn't superlight. Nor is it superbly balanced. Weight distribution is a less-than-ideal 58/42 percent front/rear, even though the engineers made several concessions for lightness and for reduced front-tire load. The battery is mounted in the trunk; the hood, front fenders, and most of the V-8 are aluminum; and the no-cost sunroof-delete option knocks off fifty pounds while adding headroom. The curb weight checks in at 3957 pounds--88 pounds heavier than the S4 and 542 pounds heavier than a BMW M3.
Surprisingly, that weight isn't as much of an issue as you would think. The stiff spring rates, the almost comically overcapable brakes (borrowed from the Lamborghini Gallardo), and the sharply focused dampers go a long way toward concealing the effects of the Audi's heft. Unlike the S4 and the S6, the RS4 doesn't plow indifferently into understeer when you push it or go wheel-numb when you start to dial in throttle under load. You can tell there's a lot of weight being tossed around, but it's never at the front of your mind. The rack-and-pinion steering is obviously muddied by that big, heavy engine perched ahead of the front axle, but it's also more direct, linear, and communicative than any Audi in recent memory. The harder you push the RS4, the more it tells you.
Plop down the RS4 on a track and, suddenly, what worked well on the street begins working even better. As on the street, mild understeer dominates, and it can be made worse if you're hamfisted with the wheel. Unlike in most Audis, however, the front-end push can be tamed with the throttle. If you turn off the high-threshold traction and stability control, you can rotate the back end under power--but only until the Torsen diff starts diverting torque to the front wheels. At that point, the chassis gently pulls itself back in line, you start to cackle, and the endless forward thrust continues. There's an almost-too-calm, might-get-you-lulled-into-trouble stability at the absolute limit, but the chassis balance is nevertheless intuitive and forgiving.
That's not to say that everything is hearts and flowers behind the wheel. As is the case with almost all Audis, ride quality isn't perfect; single-minded dampers give the RS4 excellent wheel control, but it gets tiring over rough roads and expansion joints. The steering is underboosted, it isn't as crystal clear and unadulterated as you would find in the best rear-wheel-drive sport sedans, and it remains somewhat vague at around-town speeds. The RS4-specific sport seats are supportive and stiffly padded but nevertheless become uncomfortable after extended freeway driving. And while that S button instantly turns everything into magic ear candy, it also switches on a more aggressive throttle calibration that makes smoothness difficult.
So, yes, Audi's new whiz-bang rocket ship isn't perfect. That's part of its charm. You're willing to write off its faults as the price of such asinine, iconic fun. Tear down a winding road, with pavement ripping into pieces under your right foot, and all is forgiven. The RS4 is Audi taking chances. It's special. It has soul.
The best part, though, is that the RS4 is still an Audi: It's an incredibly efficient tool for serious, controlled speed. And that's the key. The RS4 may be the evolution of the original Quattro, but more important, it's what we've always hoped every great Audi would be--flaws and all. Just when we thought the Ingolstadt crowd had gone soft, the RS4 reminds us that, once, even pedestrian Audis weren't just about cold, precise mobility. They were about driving.