2010 Audi S5

Audi has managed to keep everyone guessing about the RS5's powertrain, but the most-likely scenario is that it's powered by a modified version of the RS4's 4.2-liter V-8 tuned to make around between 450 and 500 horsepower mated to either a six-speed manual or seven-speed S tronic twin-clutch auto. And of course, expect all four wheels to be putting the power down through Audi's quattro system.

Its LED-trimmed lights, confluence of curves, and gorgeous interior make it one of Audi's most emotional and accessible designs. Yet it's not just a pretty face. With the astonishing grip of quattro and a detuned version of Audi's flagship V-8, you could call it a baby R8.

2010 Audi S5 designer Walter de'Silva has penned Alfas and Lamborghinis, but considers this his favorite.

Elemental performance sheathed in a sleek and sexy wrapper no women and few men can resist.

As for the 2010 Audi S5 Cabriolet, it receives the 2010 S4's 333-hp 325 lb-ft 3.0L supercharged V-6 and seven-speed S tronic dual-clutch gearbox a year before the S5 Coupe. In the S5 Cabriolet, this powertrain combination is good for a 0-62 time of 5.6 seconds and a claimed average fuel economy of 24.5 mpg. Available on the 2010 Audi S5 will be a new quattroSport rear differential that, similar to BMW's Dynamic Performance Control, can vary torque between the two rear wheels. Also available will be the Audi Drive Select system, which varies engine, transmission, steering, and suspension settings based on the driver's preferences. Bad news for three-pedal fans, however: A traditional manual will not be offered on either the A5 or 2010 S5 Cabriolet for the U.S.

Of the four cabriolet variants coming stateside, the 2.0T quattro strikes us as the ultimate all-around option, while the 2010 Audi S5 impresses us as the most entertaining. What about the base 2.0T and the 3.2? The front-drive 2.0T suffers from some modest torque steer as well as noticeable traction issues in the wet (the quattro version remedies both those ills) while the 3.2 simply doesn't feel as lively or robust as the 2.0T quattro (indeed, it offers 15 fewer pound-feet) or as light over its front wheels. Conversely, the 2.0T quattro drives smaller and lighter than it is, and seems to best compromise acceleration, handling, and fuel economy. But if conserving gas isn't high on the priority list, then the 2010 Audi S5 Cab is the ragtop of choice. Its smooth and whine-free supercharged engine delivers the brawniest output, while its 19-in. wheels, sport-tuned suspension, and rear diff provide the highest dynamic limits.

The 2010 S5 uses Audi's new 3.0-liter supercharged V-6, which will be phased in as a replacement for the normally aspirated 4.2-liter V-8 that's in the S5 coupe. Producing 333 hp and 325 lb-ft of torque - but no supercharger whine - it pulls the S5 to 60 mph in about five and a half seconds. The menacing V-8 sound track is replaced with a Hoover whoosh - the price we pay for downsizing - but the forced-induction V-6 provides significantly better fuel economy with comparable output.

A seven-speed dual-clutch automatic is the 2010 Audi S5's only transmission. Unfortunately, it's slow to get the 4000-pound cabrio moving off the line and painfully lethargic in its reactions to the steering-wheel-mounted shift paddles. Steering feel is surprisingly good, and unlike some other Audis, the S5 has an easily modulated, not-too-sensitive brake pedal. Despite using Audi's new powertrain layout, the nose-heavy 2010 Audi S5's engine is still mounted completely in front of the axle centerline, resulting in a strong tendency toward understeer at the limit. Rear-biased Quattro all-wheel drive and an optional torque-vectoring rear differential (also seen in the S4) do a marvelous job of counteracting this bad habit, but they're effective only under (heavy) throttle.