Each C63 AMG engine is assembled by hand, emblematic (literally, as each engine gets a signature plate) of the attention that AMG gives each car it builds. The C63 engine is magnificent, hulking under that muscular hood in all its compact glory, 6.2 liters, 451 horsepower and 443 pound-feet of torque. Too bad it's totally covered by plastic chambers, runners and plenums, making you feel pretty silly to pop the hood and admire it. You can't see pieces like the magnesium variable intake manifold. All you can say is: Well, the engine is in there somewhere, and it's real powerful.

With a redline at 7200 rpm, it sounds good, especially when your listening point is from another car and the C63 AMG passes you at 100 miles an hour. It sounds even better if it's black. If you want to fully enjoy the rumbling four-tip exhaust note of your own C63 AMG, you'll need to roll down your window a bit. From the closed cabin, it's pretty quiet.

Those great gobs of torque are located surprisingly high, peaking at 5000 rpm, although it hardly struggles at lower rpm because 370 of its 443 pound-feet of torque is available at 2000 rpm. But it's at 4000 rpm that you really feel all that torque begin to stomp you. AMG says the C63 can accelerate from 0 to 60 mph in 4.3 seconds, while Car and Driver magazine tested it at 3.9 seconds. That's quicker than the BMW M3, although the M3 is lighter and therefore a bit faster around a race track.

The C63 AMG is so smooth that 80 mph feels like 60, which is a great thing, except it makes the car a ticket trap. One hundred mph feels like 80. It doesn't take much throttle or effort to reach 100. You can get there in less than 10 seconds, and there might be jail, of course. What else could get you in that much trouble that fast, without leaving your seat? Besides a gun.

Top speed is electronically limited to 155 mph, but the performance package unleashes the car to 186 mph. Speaking of jail.

It's EPA-rated at 12 city and 19 highway miles per gallon, numbers boosted by the efficient engine and aerodynamics. Our gas mileage was 16.9 mpg, about half the time cruising at freeway speeds and the other half hammering it.

You don't always know what you're going to get with a seven-speed Mercedes transmission. They're programmed to shift based on some engineer's belief of how the vehicle will be driven. But of course this isn't a Mercedes, it's an AMG. The transmission is right.

All three modes, Comfort, Sport and Manual, are purposeful. Comfort shifts for you, at convenient and smooth places; it'll shift at redline, quickly. The Sport mode can be used appropriately, when you need the transmission to be a bit more aggressive; it doesn't kick down excessively, and makes rev-matching (throttle-blip) downshifts nicely.

The Manual mode is true, as it should be. It does something many manual modes don't; it allows you to short shift, or upshift under heavy throttle at medium revs; or even lift off the throttle and upshift at the same time. That confuses many automatic manual transmissions, but not this one.

We first drove a C63 AMG with the $3900 performance package, and found the ride uncomfortable over the harsh bumps, like weathered or cracked freeway expansion strips. After an hour in the passenger's seat, we were over it but couldn't escape it. We put our head back against the headrest, but the bumps bounced it off. It wasn't so bad in the driver's seat, but still annoying.

So we got in a model without the performance package, whose front springs are 10 percent softer, but it was still harsh. We drove that model around town, and it took the bumps fairly hard, notably in one particular concrete drainage groove.

A lot of German high-performance cars are developed on the Nurburgring, which makes their cornering fabulous. And that's what the suspension of the C63 AMG does best. AMG makes no bones about it, describing it as a "track-calibrated sport suspension," with "aggressive springs." But we ask: if the standard suspension is calibrated for the track, and suffers for that lofty goal, what about the "performance suspension" that comes with the $3900 performance package?

We got a lot of laps in the C63 AMG with the performance package, around the short course at Firebird Raceway in Phoenix. Unfortunately the track was dusty and greasy, so we didn't get anywhere near what the car does best, except maybe to test the parameters of its electronic stability control, which is well thought out.

The track time couldn't even effectively find the fade point of the massive brakes, because the performance package adds iron-aluminum composite two-piece rotors that shouldn't (and didn't) fade on a short course with autojournos driving two hot laps at a time. The basic brakes use ventilated 14.2-inch (360mm) steel rotors with six-piston calipers in front, and 13.0-inch (330 mm) rotors with four-piston calipers in the rear.

The brakes lurk behind 18-inch alloy wheels (19s are optional) with 235/40 front and 255/35 rear Pirelli P Zeroes. Jeff Andretti, former Indy car driver and son of Mario, was there with Bondurant driving instructors keeping the autojournos on track.

The corners were all second or third gear, with a moment in fourth before braking hard for another second-gear corner. The AMG Speedshift Plus transmission is quick, with Sport mode shifting 30 percent faster and Manual shifting 50 percent faster than Comfort. But Manual still couldn't keep up with the speed of the climbing engine revs, when you shifted with your foot on the floor using the excellent paddle shifters. The rev limiter came in at 7200 rpm, but you had to shift when the tach needle hit 7000 because the transmission took 200 revs to respond.

The rev matching downshifts were perfect and sounded cool, better blips than our human heel could have managed, into second gear with a manual transmission, while standing on the brakes with the toe of that same foot. The double-clutching mechanism breaks new ground. A couple times the transmission didn't obey our downshifts into second, in order to spare abuse of the gears. We had likely tried to downshift at engine revs too high and hard on the transmission, so it just refused. Chastened, we calmed down a bit on the next lap, and it cooperated.

There was a lot of tossing and sliding in the curves, making the car feel bigger than it is (its 109-inch wheelbase is tidy), and giving it the seat-of-pants illusion of being boat-like. Overall, it's well balanced, although it will understeer if driven too hard; the engine weighs 80 pounds more than the V6 in the C350, but it's mounted two inches farther back to help achieve a 54/46 weight distribution. At times it felt like the steering had too much power assist. The steering ratio is a quick 13.5. A new front axle design brings a wide track and 100 percent more rigid wheel mounting, allowing more steering precision.

The electronic stability program has three modes, C for comfort, S for sport and M for manual. We ran it on Sport the whole time, and it allowed the tail to get out there, the car drifting around the curves; the ESP only intervenes when a spinout is otherwise inevitable. We saw no need to turn it off, which is remarkable, especially for a Mercedes on the track, although we keep forgetting, this isn't a Mercedes, it's an AMG. Even if we had turned it off, we hear that it will shift back into ESP Sport, if it thinks you're out of control or even borderline.

Only once did the stability and/or traction control intervene under straight-line acceleration, when we floored it without restraint in the bumps leaving the slowest turn. The limited slip differential with the performance package is needed, there. But our ruthless floorboarding seemed to send the transmission running for Comfort, and it wouldn't go back into Manual until we brought the car to a dead stop.

But it could have been the transmission overheating, too. That happened a number of times, to different cars. When it gets hot, it locks itself out of Manual mode. It's a preservation thing. But it shouldn't happen at all. There is a large transmission oil cooler that, says AMG, "ensures non-critical operating temperatures at all times, even under extreme driving conditions." Just not in this case of less than extreme driving conditions, by journalists on a short course running two laps at a time.

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