2018 MERCEDES BENZ S 560

The S-Class powertrain overhaul appears to be more thorough than what we’ve been told to date about the Audi’s powertrain revamp. Only the boffo 621-hp/738-lb-ft biturbo V-12 and seven-speed transmission from the AMG S65 carry over largely unchanged. A V-6 returns to power the entry-level S for the first time since the S400 Hybrid variant died with the previous generation. (A hybrid is expected to rejoin this generation of S-Class within a year or two.) It’s basically the engine from the GLS450. The twin-turbo V-6 produces 362 hp and 369 lb-ft. Paired with a nine-speed automatic, it motivates this limo just as easily as it does the GLS450, which finished second in a six-way jumbo SUV Big Test in 2015.

Stepping up to the S560 buys you a detuned AMG 4.0-liter biturbo V-8 good for 463 hp and 516 lb-ft. That’s 14 more horses than the previous S500’s 4.7-liter with equivalent torque. With the nine-speed and cylinder deactivation, it also gets superior fuel economy: 17/27/21 mpg city/highway/combined versus the S550’s 16/25/20 (comparing 4Matic models—the RWD S560’s 2018 certification will not be finalized until closer to its late-2017 launch). The AMG S63’s new hot-vee 4.0-liter biturbo V-8—also with cylinder deactivation—huffs up 603 hp and 664 lb-ft—a sizeable power bump from the 2017 5.5-liter V-8’s 577 hp at equivalent torque, and it also benefits from the added leverage of two more transmission ratios (for nine here as well). This helps boost fuel economy by 10 percent (to 17/26/20 from 15/23/18 mpg). S63s also get the Race Start function from the E63, which permits you to preselect a launch rpm to suit road conditions then do a brake-torque launch (sorry hoonigans, there is no drift mode here). The 4Matic Plus system adds the ability to vary front/rear torque in place of the former fixed 33/67 front/rear split. By comparison, Audi has only released info on its base turbo V-6 and twin-turbo V-8 variants, which produce 335 hp/369 lb-ft and 453-hp/487-lb-ft, respectively. Both spin through an eight-speed transmission to standard Quattro all-wheel drive. S and possibly RS variants could follow from Audi, but Benz appears to have the mainstream A8s covered, and manufacturer claims give the Benz an edge. Actual performance could defy appearances, however, because the Audis weigh roughly 200 pounds less, and they benefit from 48-volt mild-hybridization.