Driving the 2018 BMW M550i, I can’t help but wonder what my future kid will think. Maybe in 20 years, Junior will roll a careworn M550i off the Kars R Us lot in Spokane, Washington—his gut full of regret and excitement—like I did with the decades-old Bimmers of my youth. Will the then-old BMW thrill? Challenge? Electrify? Will the kid fall in love, as I did?
BMW’s second-quickest 5-series models have a habit of turning their owners into zealots. Velvety, versatile classics like the Euro-spec E28 M535i and the E39 540i left ultimate speed honors to the more powerful M5, instead honing subtler talents like balanced handling, chuckable chassis, and all-day comfort. Our car’s window sticker—$86,685, as-tested, of soft-close door latches, cognac-colored leather, and tech galore, plus a bruiser of an engine—promises all-around greatness.
The engine delivers. If judged on thrust alone, the M550i could be chiseled into 5-series Mount Rushmore. BMW’s twin-turbo 4.4-liter V-8 routes 456 hp through an eight-speed ZF automatic and all four wheels (rear-wheel drive is not available). Turbo lag is imperceptible, with peak torque—480 lb-ft—available from 1800 to 4750 rpm. BMW claims 60 mph arrives in 3.9 seconds, quicker than the last-generation, rear-wheel-drive M5. We think that figure is modest. Mashing the throttle pedal recalls every interstellar travel sequence from Seventies sci-flicks, slamming you into vision-blurring speed.
But the chassis can’t quite hang. Even optioned with an adaptive suspension, active roll stabilization, and riding on 20-inch Michelin Pilot Super Sports, it struggles to corral 4400 pounds. Old 5-series were hefty, too, but they carried weight gracefully: You could barge into a turn, leaning hard on the front tires, and rotate smoothly off throttle. The new car performs no such stunts. Its nose, weighed down by the engine and all-wheel-drive components, must be wrestled into the slow, tight right-handers that pass for on-ramps in much of the country, and coerced, with jabs of steering, through bumpy, high-speed cloverleafs.
Those who buy big, luxury sedans will care less about at-the-limit handling than the beautiful quilted leather on the driver’s seat or the ability to adjust radio volume with a mere gesture. The 5-series has always been comfortable, but never before has it been so nice. Yet even judged purely as a luxury car, the M550i falls short. Road noise washes through the cabin at highway speed. Expansion joints ka-thwack your ears and spine. The M550i can conquer long drives (we blitzed nearly 500 miles on a full tank, returning 26 mpg at nonpuritan speeds), but senior law partners in the back seat may not feel appropriately coddled after long lunches.
The M550i seems caught between more focused choices. For sport-sedan lovers, the Lexus GS F has better steering and more charisma, and for those who’d rather be treated like royalty, the Mercedes E43 comes across as better-crafted, buttery, blissful.
The classic 5-series offered livability and performance without making you wonder how much of one you were sacrificing for the other. That’s what made them so beloved, both among luxury lessees who drove the cars off the showroom floor and the enthusiasts who plucked them off dusty used-car lots decades later. That quality fades from the 5-series with each passing year. As good as the M550i may be, it is still less resolved than its predecessors and, ultimately, less special.