An afternoon of driving three super sedans is like giving the entire world the finger, every single person, all at the same time. SUV drivers may hide behind the excuse of children, pets, or the need to move enormous holiday decorations, but there's no justifying one of these hedonistic gasoline gluttons. You flaunt one for the sheer joy of torque and tire smoke. For this very reason, the reign of beasts like these could be counting down. The EPA and CARB will crush the life out of them and force them into hiding like the American musclecars of the '60s.

With this in mind, we decided to hit the canyon roads and enjoy the big V8s to their fullest while we still had the chance. The BMW M3 and the Mercedes-Benz C63 are the newcomers, while the old guard is represented by the segment's benchmark, the Audi RS4.

Audi RS4
One could argue the Audi is the most neutral car of the three. The RS4's age is betrayed by its aesthetics. This isn't a bad thing; the big, muscular flares flexing out the fenders give it a menacing appearance. The lower shoulder line is more elegant and looks less like an armored vehicle than the Benz. The graceful curves and lack of superfluous character lines and strakes make the Audi the staff favorite in terms of looks.

Unfortunately, when pushed to the limit, its age starts to show through the chassis dynamics. With the engine hung way out over the front axle, the sensation is like trying to hustle a 911 down a mountain road, backward. Audi did an amazing job of tuning the suspension to its full potential and it works beautifully, but in the end, it's hard to get around physics. Obviously it likes to understeer in corners. In the canyons you find yourself having to brake late to get the car to rotate. The upside is that it puts down power in ways the other two cars can't. The chassis is completely unflappable in power delivery and the rear-biased Quattro all-wheel-drive system is as good as it's ever been. The front weight bias is an asset for high-speed stability. In long sweepers the car stays planted without wanting to swap ends.

Steering feel is surprisingly good for a modern Audi; most tend to be on the isolated side. There's a nice heft in steering effort that isn't there in an S4. Brake pedal feel is also world-class, the pedal itself always right there at the top of range. The consistent bite and lack of fade gives the driver confidence no matter how hard it's pushed.

The interior is the best of the bunch. Soft surfaces have a depth to them that doesn't feel like a sprayed-on afterthought. The seating position is near ideal, but the seats just don't quite compare to those in the Mercedes. But I'd estimate they're probably half the weight of the Mercedes seats, so maybe that's the trade-off.

Overall, the RS4 is the car that anyone can be fast in. It won't punish you for minor mistakes. It's always comfortable and confidence inspiring. Its look is a perfect balance of muscle and grace, while the interior is comfortable and full of high-quality components. It's not the fastest car of the group, but could be the best all-around package.

Hit*All-wheel grip *high quality materials *bulletproof fit
Miss *Heavy front end *hefty initial cost

The original E30 M3 was a true homologation special. It appealed to a select few enthusiasts who wanted a raw driving experience. Over the years, the M3 has become more grand tourer than DTM racecar, and this newest version takes it to the extreme. The best car in this group technically, it lacks the ragged edge that makes the other two so entertaining.

The M3's dynamic stability control is the biggest let down in terms of handling. It cuts power when things start getting good, and every time it activates it punishes you for the next three seconds. One tester thought it was the most intrusive stability control he'd felt in years.

The brakes never faded, but the pedal didn't feel as good as the other cars. Travel was too long and didn't give the same level of confidence. While you can get the car to move around in turns, it wasn't as entertaining as the Mercedes or as easy to drive as the Audi. That said, in the canyon the other two couldn't match its cornering speeds.

The BMW V8 seems to rev forever. It pulls reasonably well, but given the extra displacement, it doesn't feel more urgent than the previous-gen, six-cylinder E46. But as with previous generations, you really have to keep it on cam to get the most out of the engine. On a track it's fine, but in the canyon the car always seems to be in-between gears. Below 6500 rpm it feels like a regular, naturally aspirated 3 Series. We're not sure that all that displacement is really justified when the car is so wanting for more low-end torque. One staffer's first observation about the drive was, "It just doesn't feel fast enough to be an M3, certainly not a V8 M3."

When the car was delivered we found it parked right next to the RS4. The size of the M3 becomes readily apparent. It just looks more massive than the Audi. Unfortunately, it doesn't look so muscular and athletic, more bloated and overweight. In particular, the swollen hood and awkward rear valence. While the 335i is a fantastic looking car, the styling is not as effective on the M3.

Many owners will never use it for anything more than verbal racing at the martini bar. Some may use it on the track as intended, but it could be more likely the dedicated track junkie will elect to go with a 335i or 135i instead.

The car is fast, handles well, and delivers an elegant driving experience. All the things we've come to expect from the M5. The new M3 is closer to that, but without the big back seat.

Hit*Razor-sharp steering *superior overall balance
Miss *Antiseptic driving experience *rear valence like a hiked-up skirt

Mercedes-Benz C63 AMG
In terms of character, the Mercedes is the real standout. While horsepower numbers among the three look similar on paper, this thing is an absolute musclecar compared to the other two. Fifty percent more displacement and more than 100 lb-ft of extra torque put the AMG engine in a different league. Mash the loud pedal and you sink back into the seats with a force the other two don't touch. And that acceleration is there anytime, at any rpm.

Cornering is a constant controlled drift. As hard as you try, you can't get the car to be completely neutral. Turn in too abruptly and you get punishing understeer. Get it right and the back end swings around in a wider, faster arc than the front. With the three-stage stability control set on full, it's controlled and not as dangerous as it sounds. Hit the button once, and more daring tail-out action is possible with the computer curtailing your fun only when you're way out of shape.

With ESP completely defeated, the C63 could hold its own in D1 competition. Plant your right foot and the rear tires don't stand a chance. The wheels spin, the engine bellows, and you add opposite lock like a rally driver. The slide will continue as long as you want; you could even keep it sideways down the short straights between corners if you wanted.

These sideways antics illustrate the car's biggest flaw. It is quite simply under-tired. Wider tires would make this thing much faster around a track and also shave some precious tenths off its acceleration times. They might, however, dilute some of the fun.

The interior is comfortable, though lacking the high-grade materials found in the Audi. But the seats are way better than the others. When we finally build a faster-than-light spacecraft, it will no doubt be equipped with AMG seats. The big, adjustable bolsters envelop the driver like the hands of a Swedish masseuse. And miraculously, the engineers at Mercedes-AMG somehow managed to design a steering wheel equal in greatness. Unfortunately, once the seats and wheel were done, the rest of the interior was left to the fleet-car crew. A creaking glove box door and some of the thin, squeaky interior trim doesn't befit a car of this magnitude.

On the outside, the C63 looks classy, almost stealthy. It's upscale, but doesn't flaunt its ballistic performance. It wears the power bulges on the hood more convincingly than the M3 and the front fascia is aggressive without saying "boy-racer." The subtle rear lip spoiler is a nice addition, and the enormous quad exhaust tips actually look right.

The C63 is for anyone who really wants to experience what V8 power is all about, with torque the other two cars only dream about. Even the sound is pure musclecar. For all-around fun, nothing matches those big powerslides and tire-smoking escapades.

Hit*Pavement-pounding torque *incredible sport seats and steering wheel
Miss *Some cheesy interior trim *overall lack of wheel rubber

What would we buy?
*It always comes down to this: If it was our money, which one would we get?

On a curvy road, technically the best car is the BMW. It is the best balanced, lightest, and most high-tech. In the real world, however, it might be our last choice to own. The M3 has strayed from it roots and seems a slightly smaller alternative to the M5. Not that it isn't a great car-because it is; it's just that there are better options for the enthusiast, even in BMW's own showroom.

The Mercedes would be our choice if we had an exceptional lawyer on retainer. It was by far the most entertaining of the three and best represents what a V8 sedan should be. It's loud and fast, yet still comfortable. The seats and steering wheel are some of the best examples in the automotive world, but the rest of the interior is a bit of a letdown. The lack of a manual transmission could be a turnoff for some, but with the amazingly adaptive sport automatic and paddle shifters, we never found ourselves missing a stick. For a solid, daily-driven musclecar, the Benz is an obvious choice.

If gas suddenly became cheap and unlimited and we could actually live with ourselves for driving an Audi V8 every day, the RS4 could be the one. It 's a great mix of speed, handling, comfort, looks, and useability. It may be the oldest car in the group, but is still the all-around best. And its age may actually help it in terms of build quality. The RS4 was engineered before the dollar took its enormous dive. European manufacturers are struggling to build cars that still make economic sense with the current exchange rate. It will be interesting to see if the next RS4 retains the same level of quality. Until then, you could do worse than the current version.

Audi RS4 BMW M3 Mercedes-Benz C63
Layout Longitudinal front engine, rear-biased Longitudinal front engine, rear wheel drive Longitudinal front engine, rear wheel drive
Transmission 6-speed manual 6-speed manual 7-speed automatic
Suspension Multi-link (f), double wishbone (r) MacPherson strut (f),multi-link (r) MacPherson strut (f), multi-link (r)
Brake diameter (in.) 14.4 (f), 12.8 (r) 14.2 (f), 13.8 (r) 14.2 (f), 13.0 (r)
Wheels and tires 19x9, 255/35 8.5x19 (f), 9.5x19 (r) 245/35 (f), 265/35 (r) 8.0x18 (f), 9.0x18 (r)
235/45 (f), 255/35 (r)
Curb weight 3,967 lb 3,649 lb 3,814 lb
0-60 mph 4.8 sec. 4.8 sec. 4.3 sec.
Top speed 155 limited 155 limited 155 limited
Base price $66,910 $53,800 $53,800
Price as tested $71,535 $66,375 $63,930

Under the hood
*Looking at horsepower alone, you might think all three of these engines would be very similar under the skin. Once you start looking deeper into the stats you can see just how different they really are.

If you look at torque, you can see something different is going on with the C63. AMG relies on the adage of "no replacement for displacement" to get its power. Using 50 percent more displacement than the other two engines has its advantages. The Mercedes gives up horsepower per liter at the high end for down-low torque. Even with today's variable camshaft lift and duration, it's necessary for the engineer to decide what rpm range the engine should be optimized for. Obviously, Mercedes chose the lower end of the range. The result is a car that pulls hard at any revolution so the driver never feels caught out exiting a corner.

BMW and Audi both chose the upper end of the rev range, but went about it in different ways. The BMW's bore is much larger than its stroke, making for an engine more comfortable at high rpm. The swept area of the piston is greater, but the pistons have to cover less distance. This results in lower torque numbers but higher horsepower. The BMW also uses individual throttle bodies for each cylinder. This allows for faster throttle response, better optimized airflow to each cylinder, and greater resonance charging effect at high rpm.

The biggest advantage is direct fuel injection. Spraying fuel directly into the cylinder allows for better fueling along with better cylinder cooling, which also results in a more condensed and more powerful air/fuel mixture. The extra cooling effect of direct injection also allows Audi to run the highest compression ratio in the group, which results in greater power across the rev range.

All three engines have four valves per cylinder, which has shown to be the optimum layout for both power and longevity. The table also shows that all three manufacturers have chosen to use both aluminum heads and blocks. Unlike aluminum blocks of the past that required liners, the new generation of alloy engine blocks is made from a combination of aluminum and silicon. The honed cylinder bores are made of silicon crystals, which are much harder than even an iron liner. The C63 takes things a step further by using low-friction coatings on all bearing surfaces inside the motor. -MF

Audi RS4 BMW M3 Mercedes C63
Displacement 4,163cc 3,999cc 6,208cc
Valvetrain 4-valves per cylinder, dohc, intake camshaft adjustment, hydraulic valve adjustment 4-valves per cylinder, dohc, infinite camshaft adjustment, hydraulic valve adjustment 4-valves per cylinder, dohc, camshaft adjustment, hydraulic valve adjustment
Bore 84.5mm 92.0mm 102.2mm
Stroke 92.8mm 75.2mm 94.6mm
Block material Aluminum Aluminum Aluminum
Head material Aluminum Aluminum Aluminum
Fuel injection Direct injection Sequential Sequential
electronic port electronic port
Peak power 420 hp @ 7800 rpm 414 hp @ 8300 rpm 451 hp @ 6800 rpm
Peak torque 317 lb-ft @ 6000 rpm 295 lb-ft @ 3900 rpm 443 lb-ft @ 5000 rpm
Redline 8250 rpm 8400 rpm 7200 rpm
Compression ratio 12.5:1 12:1 11.3:1
Horsepower/liter 100 105 73
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