The 4.2-litre V-8 engine has been downsized to a new 3.0-litre V-6. While at first glance, this may seem like a step back - a reverse of seven horsepower -it's not all bad news for the 2010 Audi S4.
The S4, a very spirited version of the A4, barely looks the part of racy sedan, but don't be deceived by the understatement here. This car has a sweet-sounding 3.0-litre supercharged V-6 under the hood (333 horsepower).
We know this engine. It premiered in the refreshed A6, but here it's been tweaked for more power. The zero-to-100-kilometre-an-hour scoot comes in at 5.1 seconds. The linear power delivery seems to belie the fact that peak torque doesn't kick in until 2,900 rpm.
The better news is that fuel economy has improved by 37 per cent and emissions are down 30 per cent compared to the old S4. The fuel economy numbers: an estimated 13.8 litres/100 km city and 9.0 highway. Alas, you'll need to buy pricier premium fuel if you want all the performance.
There are two transmissions: a six-speed manual delivers precise shifts with short throws. The ($1,600) dual-clutch S-Tronic automatic has seven ratios and shifts smoothly through the paddle shifters - or just put it in standard auto mode.
The gearbox is worth a special mention. The double-clutch design is essentially a manual gearbox with two clutches, electric servos and a computer brain. Here, the next gear is already engaged before you need it. Once the clutch kicks in, smooth and lightning-fast shifts snap off when you want them - in milliseconds.
Inside, Audi lives up to its reputation for making some of the best cabins in the business. The materials feel expensive to touch and are a pleasure to use. The cabin has leather and Alcantara (simulated suede) for the seats. To dress things up, buyers can choose either brushed aluminum or carbon trim.
The sports seats offer lots of support without squeezing like a starving anaconda. The steering wheel adjusts for both reach and rake, and the 10-way power seats go up, down, fore and aft. You'll find a comfortable driving position whoever you are.
Moreover, the cabin has class-leading interior space: Rear passengers get most of the benefit, with plenty of head and shoulder room. Only very tall drivers will feel pinched.
The upgraded Bang & Olufsen sound system adds $1,100, while the navigation system is an extra $3,200.
The technical story begins with Audi's Quattro four-wheel-drive system, the one enhanced by a new Magna-supplied Sport differential ($1,600). Now, finally, torque is distributed across the rear wheels: If required, the outside rear wheel accelerates to push you through a curve proactively and the apportioning varies constantly. Acura's Super Handling All-Wheel Drive (SH-AWD) has been doing this for years.
The new, optional differential also comes with electronic dampers. Drivers can switch between three settings: Comfort, Auto and Dynamic. The ride quality changes from setting to setting, but so does the way the sport diff reacts. On the track, you want Dynamic, and in town, Comfort is best. The technical trickery is impressive.
Fast and manoeuvrable as it is, the S4 is safe. The car on which it is based, the A4, is a Top Safety Pick by the U.S. Insurance Institute for Highway Safety. That's the passive safety story.
On the active side, Quattro all-wheel-drive delivers serious grip, LED lights all around make the car more visible, side assist monitors blind spots during lane changes and there is the usual array of active electronic safety nannies - stability control, anti-lock braking and EBD (electronic brake-force distribution).
The S4 is a quick and nimble ride, but it's not an RS4 - which is Audi's answer to BMW's M3 and the Mercedes-Benz C63 AMG. The S4 is a bit racier than BMW's 335i and the Mercedes-Benz C350, so it lands somewhere in between.
There is plenty to admire here and the $52,500 price tag, while large in real numbers, is not outrageous in relative terms. The big issue with Audi are the various reliability hiccups generally caused by electrical components. Audi says they've been addressed and should not trouble the S4.
If so, this is some car.
2010 Audi S4
Base Price: $52,500
Engine: 3.0-litre V-6, direct-injection, DOHC
Horsepower/torque: 333 hp/325 lb-ft
Transmission: Six-speed manual/seven-speed S-tronic automatic
Fuel economy (litres/100 km): 13.8 city/9.0 highway; premium gas