The Audi is a fine compromise between the agile BMW and the monstrously fast AMG. It's superbly well planted on those winding mountain tracks; its quattro grip slingshots it from slow bends with great urgency and precision (better than either rival). The engine feels louder, bigger, and meatier than the M3's. It also revs to the stratosphere-the fun stops at 8250-though the engine is never quite as responsive as the BMW's. The six-speed manual gearshift is slower and longer of throw-but more precise and offers a smoother drive.
The steering also is more linear. As with the C63's steering, you guide the RS4 with precision and no fuss. There's more entertainment and feedback coming from the BMW's three-spoker, but, ultimately, the Audi's steering inspires more. The Audi also is roomier than the M3, has a better cabin, and delivers more performance punch in the important midrange, never mind that 0-to-60 and top-speed figures are the same. It's more fast cruiser than tearaway express, more sport sedan than sport racer. And that's just the way Audi intended it.
All three cars have different types of sport switches to boost entertainment. On the Audi, the changes include seat adjustment: The lateral wings on the driver's seat pinch your buttocks and torso a bit tighter, ready for action. We love that. Plus the engine note deepens, from V-8 grumble to V-8 rumble. Darlington, here we come.
Verdict time. The oldest car of the bunch, the RS4, is the all-arounder. Comfortable, sure-footed, roomy enough, the best cabin. The composed cruiser. Plus M3 fast. The most poised in slippery conditions. Rain hardly bothers it, not with all four wheels clawing at the road. The Audi also is best at punching its way out of tight bends.
The C63 is the fastest, the most exhilarating, the most spacious, the one that can best play at being a normal sedan. It's the car that surprised us most. Poise finally meets AMG power. In sheer performance terms it out-thrills and outpunches the M3, the breed that's ruled the small sport sedan class for two glorious decades.
But I'll take the BMW. The driver's choice. It has the best handling, the fastest cornering, the most responsive engine, and is the most nimble. Plus, when you're bearing down on the 8400-rpm cutoff, engine yowling like a Formula 1 racer, you know you're in something truly special.
Not that it's the racer's choice. For sheer speed, M3 now makes way for C63. A car that proves there is no substitute for cubes. As Detroit, home of the V-8, has known for years.
1st place: BMW M3
Driver's choice for fantastic agility, tenacious cornering grip, sky-splitting road thunder.
2nd place: Mercedes-Benz C63 AMG
Class, poise, thrills to spare and the racer's choice--almost the perfect stormer.
3rd place: Audi RS4
All-weather crowd-pleaser, ready for action, M3-fast; maybe just a bit too predictable.
| | Audi RS4 | BMW M3 | Mercedes-Benz C63 AMG |
| Base price | $69,785 | $65,500 (est) | $64,000 (est) |
| Price as tested | $73,785 | $73,500 (est) | $66,500 (est) |
| Vehicle layout | Front engine, AWD, 5-pass, 4-door sedan | Front engine, RWD, 4-pass, 2-door coupe | Front engine, RWD, 5-pass, 4-door sedan |
| Engine | 4.2L/420-hp/317-lb-ft DOHC 32-valve V-8 | 4.0L/414-hp/295-lb-ft DOHC 32-valve V-8 | 6.2L/451-hp/443-lb-ft DOHC 32-valve V-8 |
| Transmission | 6-speed manual | 6-speed manual | 7-speed automatic |
| Curb weight (f/r dist) | 3967 lb (59/41%) | 3500 lb (50/50% mfr est) | 3800 lb (52/48% mfr est) |
| Wheelbase | 104.3 in | 101.7 in | 108.9 in |
| Length x width x height | 180.7 x 71.5 x 55.7 in | 181.7 x 71.5 x 55.8 in | 186.0 x 70.7 x 56.6 in |
| 0-60 mph | 4.5 sec | 4.6 sec (MT est) | 4.3 sec (mfr est) |
| EPA city/hwy fuel econ | 13/20 mpg | 14/21 mpg (est) | 13/20 mpg (est) |
| CO2 emissions | 1.26 lb/mile | 1.18 lb/mile (est) | 1.26 lb/mile (est) |
| On sale in the U.S. | Currently | Spring 2008 | Spring 2008 |