The car enthusiast community in America is celebrating and with good reason: the 2020 Audi RS 6 Avant super wagon is actually coming to the U.S. But there's more reason to be excited. With the Audi coming, Americans will be able to choose between two super wagons. In addition to the Audi, the Mercedes-AMG E 63 S wagon is still available. While we won't be able to say for sure which is better until we've driven the Audi, we can at least look at the specifications of each wagon to see how they compare. We've assembled the salient details in the chart below, and following that is some detailed analysis.
Engines and performance
Both German wagons choose very similar paths to performance. Each uses a twin-turbocharged 4.0-liter V8, an automatic transmission and all-wheel drive. The Audi is the less-powerful of the pair with 591 horsepower and 590 pound-feet of torque compared to the Merc's 603 horsepower and 627 pound-feet of torque. That difference comes through in 0-60 mph times of 3.6 seconds for the Audi and 3.4 for the Mercedes. But in real life, you'd have a hard time noticing that difference. The Mercedes also has a higher top speed, but both are electronically limited, so Audi could hypothetically offer an option to change the speed limiter.
The drivetrain is where the two differ more. The obvious difference is that the Mercedes has an extra ratio in its transmission. The less obvious difference is in the all-wheel-drive system. Both cars can adjust the torque split between the front and rear wheels to favor the rear, but only the Mercedes can send 100% of its power to the rear wheels using its "Drift Mode." The Audi is limited to sending 85% of its power to the back. So the Mercedes may be the wagon of choice for people who want maximum, on-demand tire destruction.
Also worth noting are the suspension options for these wagons. Or specifically for the Audi. It comes standard with a sporty air suspension setup, but it can be had with a more conventional performance suspension with steel springs rather than air. The Mercedes on the other hand is only available with air suspension.
Interior and exterior dimensions
Going fast is great, but station wagons need to be practical, too. Using dimensions from the A6 Avant and A6 sedan as a guide, since official RS 6 dimensions aren't available yet, we can see the two are very close. From the outside, the Mercedes is just a couple inches wider and longer. But the small difference on the outside yields a big cargo space advantage for the Mercedes. With the rear seats up or down, the Mercedes has about 15 more cubic feet of cargo space than the Audi. That's a difference of an average small sedan's trunk. The Audi does at least boast a back seat with about two more inches of leg room. The rest of the passenger space dimensions are pretty even.