Audi RS4 Cabriolet

At first glance the new Audi RS4 Cabriolet looks very similar to the A4 and S4 drop-tops on which it's based. But look closer and the lowered ride height and pronounced fender flares strongly suggest that this vehicle is something special. That impression is heightened by twin oval exhaust tips the size of coffee cans poking out from the rear diffuser.

The bulging fenders are not ornamental; neither are the exhausts. The wider bodywork is necessary to accommodate the RS4's greater track, up 1.6 in. at the front, 1.9 in. in the rear, compared to its lower-powered siblings. The fat exhausts help extract the considerable volume of spent gasses expelled by its hard-working V-8.

That powerplant is the centerpiece of the RS4. It's a comprehensively tweaked version of the corporate 4.2-liter V-8 using a familiar recipe: Improve airflow, beef up the internals and spin the engine faster--up to 8250 rpm in this case. The direct-injected engine gets new, stronger forged pistons, bumping the compression ratio to a stratospheric 12.5:1, further increasing efficiency and sharpening throttle response somewhat in the process.

The 4.2-liter is a jewel of an engine which, along with the BMW M3's 4.0-liter, ranks among the world's highest-revving road-going V-8s. Both also join the very exclusive club of engines breaking the 100 hp-per-liter barrier.

Peak power jumps from the S4's 340 hp to 420 hp, reached at 7800 rpm. Torque improves marginally to 317 lb-ft, 15 more than the S4 enjoys. Its peak arrives at 5500 rpm (versus 3500 rpm for the S4) with 90 percent of that available between 2250 rpm and 7600 rpm. Despite its modest displacement, from 3500 rpm to redline it generates impressive levels of thrust all across the powerband.

A short-throw shifter works the 6-speed manual's closely-spaced gears. In normal driving a shift to second is in order nearly as soon as the wheels have begun turning and to fourth by 40 mph. That cog is the all-around utility gear, providing strong acceleration from near-walking speed up to 120 mph.

The RS4 receives the expected enhancements to stopping power (14.4-inch-diameter, eight-piston front brakes) and suspension tuning, along with revisions to the steering, stability-control system and related subsystems. Shorter intermediate gearing and a stout 4.11:1 final drive help keep the engine in the sweet part of its powerband.

Despite a pronounced front weight bias and a hefty 4,068 pounds of mass to cope with, the RS4 does a passable imitation of a rear-drive car. Credit this in large part to clever suspension setup and the Quattro all-wheel drive's seamless apportioning of power between the axles.

Steering response is instantaneous and nearly telepathic. Pressed hard a corner, the Audi quickly takes a set and tracks obediently through, complacently allowing mid-course corrections if the driver gets it wrong. Smooth control inputs are rewarded with gratifyingly high cornering forces without any second-guessing from the electronic stability system. The latter allows the tail to be rotated to a degree, although once the limit is reached, the RS4 lapses into benign understeer to protect the unwary.

Spot-on suspension tuning unobtrusively masks road imperfections while keeping body motions well in check. There's minimal body roll although like in many Audis, when flogged there's a noticeable amount of acceleration squat.

Regardless of speed, it's an extremely easy car to drive quickly. With stability control engaged, it takes considerable effort to get the car crossed-up, allowing even a marginally-talented driver to look positively heroic at seven-tenths or less.

Many of these cars will see weekend track duty, making the standard electronic lap timer a useful piece of kit. There's also a Sport button that somewhat sharpens throttle response while opening baffles in the mufflers. The reduction in backpressure also increases sound levels while altering the V-8's glorious tenor into a confused babble. In the end, we left it switched off to better savor the RS4's intoxicating exhaust note.

Performance is impressive, if not quite as ear bleed-fast as the competition. The test car did 0-60 mph in 5.0 seconds and cleared the quarter-mile in 13.35 at 103.3 mph. Both numbers are slower than Audi quotes, but perhaps they found a way to bypass the 3500 rpm first-gear limiter that prevents dumping the clutch at high revs.

Maximum speed is quoted as being limited to 155 mph although the last S4 6-speed we drove managed 167 mph despite the limiter, and this one is significantly faster. But this car's mission statement doesn't focus only on straight-line speed.

The RS4 is all about balanced performance, that elusive mix of power, handling and brakes plus everyday practicality. The other Germans may be quicker but none offers more driving enjoyment. This Audi is one of those rare automobiles that's so enjoyable to drive, it entices one to create excuses to take it out for a romp.

At $81,900, the lavishly-equipped Cabriolet is base-priced a cool 15 large higher than the RS4 sedan. But Audi plans to build only 300 examples, which may justify the tariff. For the budget-conscious, the sedan may seem the better deal. But we'd suggest first driving a Cabriolet with the top down, taking it to the redline a few times. The aural entertainment alone may well be worth the price of admission.

Editor's Note: You're here already, so check out the secrets to driving a car like this without losing your license.