2019 Audi A7 and Mercedes-Benz CLS450 Face Off in a Luxury-Coupe Battle

Turbocharged 3.0-liter six-cylinders power both cars. The Audi arranges its six pots in a vee while the Mercedes has its lined up in a row.

The Mercedes is also hybridized with a 48-volt motor-generator sandwiched between the engine and transmission that pitches in with another 21 horsepower when asked. The Audi, meanwhile, features a 48-volt motor-generator connected via a belt; it helps the engine's stop-start system but doesn't do anything to move the A7.

Both cars carry a full load of technology as all current luxury cars must. There's more computing power in the infotainment systems of these cars than there was available to NASA when it, along with Stanley Kubrick, faked those "moon landings." Accordingly, they're pricey. The Audi bases at $68,995 and inflates to $83,240 as tested while the Benz starts at $72,695 and bloats to $94,540.

Don't let the sleek rooflines, the frameless window glass, or the manufacturers' propaganda tempt you into believing these are coupes. They're mid-size four-doors with slicked-back hair, more fashionable than the upright Audi A6 and Mercedes E-class sedans with which they share most of their mechanical substance.

What the A7 has is immediacy, an instant response to every input from the driver.

Its quick, linear, predictable, and tactile reflexes beget the sort of connection between driver and machine that's exciting entering a corner, confident going through it, and satisfying coming out.

Forget the Knight Rider–style scanning LED light show that the head- and taillights put on every time you fire up the A7. That's just a distraction. This isn't a car that relies on electronics to simulate intimacy, but one carefully built around technology to enhance the joy of partnering with something mechanical.

Relative to the Jell-O–mold styling of the CLS, this second-generation A7 is sharper and more aggressive, yet somehow less self-consciously sporty-looking. It has a faceted muscularity that the CLS lacks and that the first A7 didn't have, either.

Critically, it also has triangular side windows in its C-pillars that open up the cabin to more light and keep it from feeling cramped.

Plus the whole interior is gorgeous and uses tricks like a cutout headliner to improve headroom for rear-seat passengers.

With the exhaust ports aimed into the valley between the V-6's cylinder banks, Audi uses alternating exhaust gases from both banks to feed the blower's twin-scroll turbine.

Turbo lag is therefore nearly nonexistent in the new engine, and the torque starts building from just off idle. It's not as creamy as the straight-six in the Benz, but it feeds a seven-speed dual-clutch automatic transmission with satisfyingly quick shifts.

But it's the A7's Virtual Cockpit and MMI Touch Response infotainment systems that will attract the most attention. Built around three high-resolution displays-two of which are touchscreens with haptic feedback-and included as part of the massive $8300 Prestige package, the Audi electronics set a new stand­ard for this stuff.

The chassis is equally unfazed by the heft. The A7 knows when to pivot and when to plant its feet in corners. Body control is kept in check, and its transitional behavior is quite fluid. Even on the optional 21-inch wheels, it treads lightly over imperfections.

Surprisingly, since the Mercedes carried an extra $1100 of sound deadening, the Audi proved at least as quiet under most circumstances. Some credit for that must go to the A7's new 255/35R-21 Bridgestone Turanza T005 grand-touring summer tires.

The Mercedes CLS-class is the original. Fifteen years ago, when upright four-doors were still acceptable in polite company, that first CLS pioneered the chopped-fastback-roof profile that has spread throughout what's left of today's sedan market. This new one is the third-generation CLS, and its style is consistent with the previous two but a bit more gelatinous.

Number for number, the CLS450's performance is practically indistinguishable from the A7's. Both cars leap from zero to 60 mph in 4.4 seconds, both pull 0.93 g on the skidpad, and their 70-to-zero stopping distances are within five feet of each other.

At a 70-mph cruise, both cabins hum with a mere 63 decibels of noise, and after 450 miles of driving, these Germans both returned 20 mpg. Top speed? They're both governed to 129 mph.

In some ways, the CLS's interior is clearly superior to that of the A7.

The seats are better shaped, the steering wheel has a beefier handshake, and the optional head-up display is easy to read. But it feels cramped and claustrophobic.

And while the 12.3-inch widescreen display atop the dash is beautiful, its menus seem laid out for a touchscreen, not a click-wheel controller and touchpad. Compared with the audible and haptic feedback of the Audi's multitouchscreen system, the Mercedes' setup feels so 2009.

On top of all that, there's that pricing disparity. Toss the M-B's $5400 Burmester surround-sound system overboard and the Audi's advantage is still $5870. That seals the CLS's second-place finish.

The nine-speed automatic shifts softly using the steering-wheel-mounted paddles, and when left to swap gears itself, it never seems eager. As willing as the engine is, the rest of the powertrain is a shoulder shrug away from indifferent. The satisfying sensations of a direct mechanical connection are lost in the torque-smoothing grace of the electric motor, the torque converter, and nine tight gear ratios.

As with the A7, the CLS's interior design is startlingly good. Accented in silvery wood and featuring large circular vents that could blow out a named hurricane, the dash is all very tasteful. Well, almost all.

Ambient lighting featuring 64 different colors is available, and the driver can choose to let them constantly cycle so that it's like driving through a psychedelic Ruth's Chris Steak House. Not exactly tasteful, but tasty.

Still, the combination of 245/40R-19 front and 275/35R-19 rear Goodyear Eagle F1 Asymmetric 3 run-flat tires and optional air springs with the 4MATIC system made for tenacious grip even on slimy roads.

It's easy to go very quickly without realizing it. But the CLS's structure feels flimsy. Hit even the smallest road divot and a shudder rolls through the car that all the occupants hear and that the driver feels in the steering column. This happens no matter what drive mode the suspension is in, and it's not at all Mercedes-like.

Deciding between these two comes down to more-subjective evaluations. With a subdued and almost soothing snarl, the new Mercedes straight-six doesn't rev as much as it unfurls. There's no feeling of the turbocharger kicking in, just a ribbon of torque. Oddly, though the Mercedes' long-stroke six is rated at 362 horsepower-up 27 on the Audi-both engines carry peak-torque ratings of 369 pound-feet.