We’ve watched two Gulfstreams and a Learjet touch down in a span of 30 minutes, taxi along the stretch of pavement we’re using as our provisional test track, and tuck into spotless hangars. Only the flight crews disembark from these planes. The nondescript southern German village of Schwäbisch Hall, population 40,000, isn’t the kind of place where you’d reside if you could afford to live anywhere. From what we can tell, this airfield is the EZ-In/EZ-Out parking garage for the planes of one-percenters who reside elsewhere. Suddenly, our collection of $100,000-plus four-seaters doesn’t seem so extravagant. Aside from a private jet, however, few vehicles make our test trio look humble. When you’re grounded, there’s no better way to travel than in Audi’s RS7, BMW’s M6 Gran Coupe, or Mercedes-Benz’s CLS63 AMG. Each of these three automakers has a larger, more opulent flagship if you intend to ride in the back seat. The RS7, the M6, and the CLS63, however, are the top machines for those who insist on driving. Speed barons, kings of luxury, and fashion slaves, these cars exist in the overlap of an exotic automotive Venn diagram. Germany’s de-restricted sections of autobahn are as close as the earthbound can get to the freedom of flying. Yet even 10-mile stretches aren’t enough to achieve top speeds, which in our cars are as high as 190 mph—a white van always seemed to veer into the left lane every few miles doing a mere 100 mph. A great test of the brakes, that.
And because a tank of gas only lasts 40 minutes when there aren’t speed limits, we trekked away from the freeway to a sinuous, tree-lined hill-climb to understand how differentials, adaptive dampers, and gummy tires shrink these large cars when the road starts twisting. Audi waltzes into this bout with an overflowing trophy case. The A7 already knocked out the CLS550 and the 640i Gran Coupe in separate matchups. In our last Audi-BMW-Benz comparo [July 2012], the S6 shrugged off a roughly 100-hp deficit to topple the E63 AMG and the M5. This time around, Audi’s entry is fighting in its weight class. The RS7 comes from Quattro GmbH, Audi’s answer to the M and AMG organizations. As in the S6 and S7, its power comes from 4.0 liters of twin-turbocharged V-8, but the R in RS7 means 140 more horsepower and 110 more pound-feet of torque matched with a sophisticated suspension and, in the case of our test car, optional carbon-ceramic brakes. And as the only hatchback in this set, the RS7 boasts cargo space the others can’t match.
BMW’s M6 Gran Coupe, on the other hand, faces an uphill battle. Its good looks can’t mask its close kinship to the disappointing M5 that placed last in our previous test. The Gran Coupe rides on the same 116.7-inch wheelbase, is powered by the same 4.4-liter blown V-8, and uses many of the same chassis components as its 5-series equivalent. Ponderous and plodding, the M5 shuns M-brand hallmarks of litheness and agility. But it should be noted that the M division’s philosophical approach with the Gran Coupe—how it tunes the bushings, springs, dampers, and anti-roll bars—sounds closer to how it views the sharper, sportier M6 coupe than the bulky M5 sedan.