What makes the E63 so special is the blend of its abilities. For a start, it's a particularly emotional machine-mean-looking, acoustically overwhelming, and very fast, yet it can be either velvety smooth or bondage brutal, whichever you wish. True, the stability-control warning light may flash in the wet at 125 mph, but you won't feel more than a tug or a kick, and then it's full urge again all the way to the 7200-rpm redline. Unlike the supercharged E55, which was so pumped up with hormones it could hardly accelerate in a straight line, the follow-up model is a lot more relaxed, more sure-footed, and quite a bit quicker. By a wafer-thin margin, the Benz has the most compelling engine. It wins the torque trophy and the acceleration medal, it sounds awesome, it's mated to a transmission that confines itself to only three shift programs, and its relentless push extends into the triple-digit speed zone. What this car needs to move even closer to perfection are brakes with extra staying power and steering that can do more than change direction.