2008 BMW M3 Sedan vs. 2008 Mercedes-Benz C63 AMG Comparison Test

There will be no Camaro vs. Mustang death match this week due to a distinct lack of Camaro, so can we interest you instead in a muscle-car comparison test? Here we have two classic nameplates, each with a 400-horsepower V8 stuffed into a smallish four-door body shell and powering only the rear wheels.

Naturally we're referring to those two paragons of modern muscle, the 2008 BMW M3 Sedan and the 2008 Mercedes-Benz C63 AMG.

Don't be confused by the German nameplates, the aura of high-tech engineering and the rarefied price tags. The 2008 BMW M3 Sedan and 2008 Mercedes-Benz C63 AMG match up as naturally as any muscle cars on Woodward Avenue during the 1960s.

The Contenders
The 2008 BMW M3 Sedan marks a return of the four-door sedan to the M3 family, a variant that skipped the previous generation only because of engineering complications, not market appeal. This M3 packs a 4.0-liter V8 that is essentially the M5's 5.0-liter V10, only with two fewer cylinders. It steps up the M3's game to a new level of performance with 81 hp more, even though it actually weighs less than the last-generation M3's inline-6.

Compared to the 2008 BMW M3 coupe, the 2008 BMW M3 Sedan gains almost 100 pounds and loses the fancy carbon-fiber roof. There are advantages, however, as the sedan lops nearly $3 grand off the coupe's sticker with a base price of $54,575. This a pretty compelling incentive to consider an extra (and very convenient) set of doors for your M3. Once optioned with the Cold Weather package, Premium package, Technology package, 19-inch wheels, moonroof, iPod and USB adapter, Park Distance Control and HD radio, our M3 test car costs $65,850.

The 2008 Mercedes-Benz C63 AMG stuffs a DOHC 6.2-liter V8 under the hood of the meek C-Class sedan, widens the front track and turns the aggression factor up to 11. For the C63, the corporate AMG V8 has been detuned by more than 65 hp compared to examples of this engine in other AMG models, and we suspect this has as much to do with the car's pecking order in the AMG model lineup as it does with technical reasons (cooling has been mentioned), but, hey, we're not complaining. Base price is $54,625, and for $65,785 you get a C63 equipped with the AMG Performance package, Multimedia package, Seating package, metallic paint and TeleAid.

With just $65 separating the as-tested prices of the 2008 BMW M3 Sedan and 2008 Mercedes-Benz C63 AMG, these cars match up in price as well as market position. But as with muscle cars of the past, pure performance is the raison d'être of these sedans, so this is what this comparison is all about.

One V8 Is From Venus; the Other Is From Mars
Based on first impressions, you'd be hard-pressed to guess that the 2008 BMW M3's 4.0-liter V8 will spin out 414 hp and run clear to 8,400 rpm before the rev limiter cuts in. It spits hoarsely at idle and its drivability is a bit sticky when it's stone cold.

Once there's some heat in it, BMW's V8 reacts to throttle inputs with crystal-clear response, due in part to the individual throttles for each cylinder. This engine is so free to rev — particularly when the Power mode is selected, which ramps up the effect of the throttle pedal sooner in its travel — that it's almost as if it has no internal inertia at all. Nevertheless, this engine also boasts a surprising tractability that belies its relatively modest peak torque rating of 295 pound-feet.

If a crushing midrange is what you want, look no further than the AMG V8. The 6.2-liter V8 gives the C-Class the irresistible force of an avalanche, no matter whether the tachometer needle is pointing toward 2 or 7. Plant the throttle on the floor and the large-displacement V8's 451 hp and 443 lb-ft of torque will paint two black stripes of rubber on the tarmac through the first three gears. When driven in anger, the C63 is one of those rare cars that feels even quicker than its output suggests.

Upshifts from the C63's seven-speed automatic transmission come readily when in auto mode and the speed just piles on without much interruption. This autobox will even match revs during downshifts, though there's a brief delay when commanding shifts manually from the wheel-mounted shift paddles. The BMW's three-pedal-layout manual transmission neatly sidesteps these compromises, although BMW will offer a seven-speed twin-clutch automated manual gearbox for the M3 later this year that will deliver automatic action.

Both engines do the Jekyll and Hyde thing quite convincingly, and ultimately the biggest difference lies in character. The M3's V8 is as swift and sharp as a katana sword, while the C63's V8 punches like a set of brass knuckles. And whereas the M3 sounds best when it's being caned ruthlessly, the C63 barks like a beast when you simply twist the key and start it.

Running the Numbers
Despite boasting similar power-to-weight ratios, the C63 runs notably quicker than the M3 sedan in a straight line. It clicks off the quarter-mile in 12.5 seconds at 113.7 mph, compared to the BMW's 12.9 seconds at 111.1 mph, an advantage of 0.4 second and 2.6 mph. Likewise, 60 mph comes up in 4.1 seconds in the Benz and 4.5 seconds in the Bimmer.

These are no lightweights, as the BMW weighs in at 3,686 pounds while the C63 weighs just 7 pounds shy of 2 tons at 3,993 pounds. Even so, braking from 60 mph proves no challenge for the BMW, which stops in 104 feet, some 10 feet shorter than the Benz's 114 feet and with less brake fade than the Benz besides.

With its big-inch motor and efficiency-sapping automatic transmission, the hefty AMG treats a gas card like a doormat when you drive it like we did, averaging 15.3 mpg in mixed driving. The M3 is a shade less thirsty at 17.8 mpg.

Lapping Spring Mountain Raceway
With the C63 proving decisively quicker in a straight line and the M3 treading its way to superior slalom and skid pad performances, we have what appears to be a dynamic stalemate among these two Teutonic forces. Or do we? To settle the matter, we lapped the 1.5-mile west loop of Spring Mountain Motorsports Ranch in Pahrump, Nevada. Veteran Edmunds tester Josh Jacquot ran the timed laps which were recorded and analyzed using our GPS-based VBOX logging equipment.

Both the M3 and the C63 were able to top 100 mph on the main straight, where the C63's thunderous acceleration nearly closes the gap on the M3. However, it is the M3 that reaches a higher max speed on the main straight — 106.2 mph to the C63's 104.5 — before braking hard for the tightest section of the track. The C63's quick-shifting autobox was less of a liability than we expected, though its lingering autonomy still left us wanting for a true manual gearbox.

The M3's weight advantage and superior grip proved indomitable in quick transitions, giving it the ability to corner at higher speeds and brake later than the C63. In fact, on most of the track's ten turns of varying severity, the M3 is able to consistently brake deeper and uses its higher grip and more predictable manners to its advantage when subjected to the cold, unblinking eye of our testing equipment. The quickest lap for the M3 was 1:24.0 to the C63's 1:25.8.

Subjectively, the M3 is the more involving drive here. It encourages the driver to press on beyond the limit of tire adhesion, whereas the C63's somewhat less communicative nature doesn't inspire this level of confidence. In fact, the C63's quickest laps were found to be with the stability control in its most aggressive setting rather than switched fully off. Although a faster track with longer straights would likely play to the C63's favor in terms of lap times, the M3's fundamental goodness would remain.

M3: Inner Duality
When it's driven around town, there's little indication that the latest M3 is much more than a firmed-up 3 Series with a pregnant hood and a kielbasa-thick rim to the steering wheel. The slick clutch takeup and positive (though slightly long throw) shift action are just like what you'll find in most modern BMWs despite this highly tuned V8, while the steering effort is a bit lighter at parking lot speeds than even a base 3 Series.

Leave town and find your favorite canyon road. Punch up the M3's optional electronic damper control (EDC), which covers the range of suspension stiffness in three steps from easy cruise to track-only firm. Once its damping is set to the relaxed mode, the M3 breezes over the high-frequency choppiness of concrete freeways, while the additional control provided by the middle setting is required for roads with quick left-right-left transitions.

Likewise, the M3's steering betrays an inner duality, as its effort level is relaxed enough for you to maintain stress-free high-speed cruising, while it's responsive enough that midcorner steering adjustments result in immediate course correction.

The Corner Connection
Make your way through a series of bends at a moderate pace and the chassis responds with confidence, although it feels slightly inert. Overall, the M3 has a forgiving demeanor and the nose of the car always leads the way. You're left with the impression that the process of polishing the M3's dynamic skill to achieve a sheen of refinement has inadvertently led the M division to wipe away a modicum of the M3's character.

But once you start to explore its limits, the M3 gradually reveals the depths of its talent. It turns out that the handling balance is more neutral than you've been led to expect, but you have to show some serious commitment to extract this character on dry pavement. This is a chassis that needs to be worked hard, and it grips the road like Paul Bunyan armed with a set of channel locks.

Once you truly commit to loading the tires all the way from the turn-in point to the exit of the corner, the M3 responds with more grip and less understeer. Even when driven on the limit of adhesion, this is not some twitchy, overpowered rear-drive car. Throttle inputs have to be provocative to summon power oversteer, and even then the rear end's trajectory in a corner changes progressively.

C63: Point and Squirt
In comparison, the 2008 Mercedes-Benz C63 AMG is more of a point-and-squirt machine. Equipped with the optional Performance package that includes a limited-slip differential and firmer damping, the C63's body remains astonishingly flat through rapid cornering transitions, while the steering with its caster-heavy geometry delivers excellent precision and appropriate quickness. And even though the C63 has the nose-heavy weight distribution you'd expect after shoehorning a V8 in the front of a compact C-Class sedan, this doesn't translate into the punishing understeer you might have expected.

With a performance of 0.89g on the skid pad, the C63's ultimate grip is only a bit less than the M3's effort of 0.93g. There's not as much tactile feedback through the C63's steering wheel as the M3's, however, and there's less warning should the C63's rear end break traction while exiting a fast turn under power. It's not at all tricky, but the C63 doesn't inspire the same confidence as the M3 near the cornering limit.

The Corner Connection 2
The C63 is nevertheless a blast to drive hard on rotini-twisted roads, even if it might not be able to keep pace with the leaner M3 from point to point. For example, the C63 AMG's 68.6-mph effort through the slalom lags behind the M3's 71.8-mph performance by some margin. But if powersliding hooliganism is more your style, then the C63 is your choice, since it'll sustain a tail-out attitude around a corner until the steel cords show through the rear tires.

The brutally stiff damping rates of this C63 with its AMG performance package can't hope to deliver the supple ride of the M3's multimode dampers. This AMG rides like an iron fist in an iron glove, and you have no other choice if you want the limited-slip differential, as the AMG options grouping says that if you want tire traction you must have suspension control, too. And with this much power on tap, the diff is a must.

The Performance package also includes a set of seats with side bolsters so pronounced that you have to swing your hips forward like you're twirling a hula hoop to avoid them as you clamber inside. These chairs are outstanding for high-speed canyon carving, but less so for daily use.

Bottom Line
Of course the 2008 BMW M3 Sedan and 2008 Mercedes-Benz C63 AMG aren't exactly muscle cars, no matter how much rubber they'll leave on the pavement.

The C63 is one of a new breed of AMG cars, much closer to the spirit of the CLK63 AMG Black Series than its forebears, and if this trend signals a change in corporate philosophy, we welcome it. This effort amounts to much more than simply a big engine in a small car. Instead the C63 brings a range of dynamic talents to the table that has been missing in previous AMG models. The 2008 Mercedes-Benz C63 AMG also crackles with character, something the M3 could use a bit more of.

For all this, the 2008 BMW M3 Sedan's breadth of competence is insurmountable in this comparison. The BMW just does so many things so damned well, and this spectrum of talent really defines what the M3 is all about. The M3 can be many things to many different drivers without unduly compromising its ability to perform for any one of them. This is the mark of a very special car, and it makes the BMW M3 sedan the winner in this comparison.

The manufacturers provided Edmunds these vehicles for the purposes of evaluation.

Features

Key:
S: Standard
O: Optional
N/A: Not Available

Limited-slip differential: The C63 requires you to tick the Performance package option to get a limited-slip. In a rear-wheel-drive car with more than 450 hp, this is a baffling oversight.

Manual gearbox: Although it has a manual mode, the C63's automatic is no substitute for a true manual gearbox.

Multimode dampers: The BMW M3 allows the driver to select from three distinct levels of suspension firmness and control.

Navigation system: More than directions, a navigation system is like a personal assistant.

Editorial Director Kevin Smith says:
I'm amazed and a little unsettled to hear myself say this, but I like the C63's character better than the M3's.

That's news because ever since the Big Bang, I have almost always preferred the balanced, poised, athletic and communicative nature of BMWs over the beefy, trucklike feel of the equivalent Mercedes. And the current C-Class and 3 Series offerings have done nothing to change that balance of power.

Until now.

I still grouse about the whiff of numbness in the C63 AMG's steering, and if you're really whomping on it in a racetrack setting, the car can get to feeling a bit front-heavy (as you would, too, with 6,208cc of V8 stuffed in your nose). But then I hear that exhaust rumble. I feel a couple sharp, rev-matched downshifts on braking. I note how the stiff Performance package suspension speaks to me loud and clear about the pavement texture. And above all, I revel in the sheer thrust the engine generates, and I think, wow. This car is very cool.

After that, I get in the new V8-powered M3, a car I fully expect to be smitten by, as most arbiters of automotive taste have said I would be, and it feels, well, soft. Not boring, and certainly not slow. But also not as raucous and gutsy as the C63. Should I appreciate, maybe even prefer, the M3's higher level of refinement and polish? Probably. But if I could choose either of these to put a quick thousand miles on right now, amazingly enough, I'd go for the truck with the loud motor and the stiff legs. It's a lot more fun to hang out with.

Final Rankings

Personal Rating (2.5%): Purely subjective. After the test, each participating editor was asked to rank the vehicles in order of preference based on which he or she would buy if money were no object.

Recommended Rating (2.5%): After the test, each participating editor was asked to rank the vehicles in order of preference based on which he or she thought would be best for the average consumer shopping in this segment.

20-Point Evaluation (25%): Each participating editor ranked each vehicle based on a comprehensive 20-point evaluation. The evaluation covered everything from exterior design to cupholders. Scoring was calculated on a point system, and the scores listed are averages based on all test participants' evaluations.

Feature Content (15%): For this category, the editors picked the top 4 features that would distinguish one vehicle from the other. Standard, optional (and included), and optional (but not included) equipment were taken into consideration.

Performance Testing (35%): For this particular comparison, we've weighted the vehicles' track performances greater than one for, say, minivans. Flat-out acceleration, braking and handling tests were performed in a controlled environment by the same driver on the same day.

Price (20%): The numbers listed were the result of a simple percentage calculation based on the less expensive vehicle in the comparison test. Using the "as tested" prices of the actual evaluation vehicles, the less expensive vehicle received a score of 100, with the remaining vehicle receiving a lesser score based on how much it costs.