Why buy an M5 when you can have an M550i? You could call it the M5-Lite or the poor man’s M5, but not only do I think the M550i is the better value, but it’s cheaper, more comfortable, less ostentatious, and carries with it a boost-chugging V8 reactor that delivers near-M5 levels of acceleration and performance without the stiff damper setup or expensive tires. We share the same sentiment with the 8 Series portfolio, where the M850i is just so darn spectacular that the M8 is almost rendered obsolete – okay, that last point may be overly exaggerated but you get the point. 

Utilizing a similar 4.4-litre twin-turbo V8 to the M5, the M550i produces an impressive 523 hp and 553 lb-ft of torque, 68 hp and 73 lb-ft more than the 2019 model. That’s the same engine tune as the M850i, and the same amount of torque as the M5 Competition. Relaying all that prodigious power is an 8-speed transmission that has been massaged out for quick yet polished shifts and like the M5, the M550i is all-wheel drive only but cannot disconnect the front axle for drifting shenanigans. That’s okay. I am not sure who would be shredding hundreds of dollars worth of Michelin rubber anyways.

BMW hasn’t quoted an exact 0-100 km/h for this new 2020 model, but our 2018 M550i did it in 4.0 seconds flat, so we can only assume the uprated power output should shave off a tenth of a second. To put that into perspective, this hotrod luxury sedan is quicker than the last generation F10 M5 and it further obliterates other ‘mid-way’ performance sedans like the Mercedes-AMG E 43 (396-hp, 384 lb-ft) and Audi S6 (450-hp, 406 lb-ft), both of which make considerably less power and are slower in a straight line as well. Embarassing exotic names like the Maserati Ghibli, this sleeper M550i actually lives in the same speed realm as considerably more hardcore fighters like the Audi RS5 (3.9 s) and Mercedes-AMG C 63 S Sedan (4.0 s). I would also keep in mind the fact that BMW tends to underrate their power outputs – we have heard many dyno reports of the M550i making its claimed output, at the wheels.

Cosmetically, the M550i hasn’t changed, and sets itself apart from other 5 Series models with a rear spoiler and Cerium Gray finishes on the mirror caps, kidney grill, and front air intakes. The M550i also receives an M sports exhaust with black chrome tailpipes, door sills with an illuminated M550i inscription, glossy black trim around the window sills, standard sport seats, and aluminum pedals. It also rides 10mm lower than the standard 5 Series. In all, the M550i doesn’t appear all that different from your run of the mill 540i. Some will appreciate that sleeper status award, but something tells me that many BMW owners want a little more flair – hence the justification for the M5. I would get rid of those geeky M badges on the side fenders, though. They look out of place on this gentleman of a ride.

And the same goes for the driving experience. When cruising along at city speeds, the M550i is as gentlemanly as they come. When set to Comfort, the suspension is soft, lenient, and forgiving. Potholes are absorbed like a sponge with no residual shake felt by passengers. There’s some body roll in corners but the overall vehicle feels taut and tucked in. The exhaust is subdued but authoritative when throttle is applied, steering is light, the 8-speed shifts imperceptibly, and overall ride quality is serene and luxurious.

But when Sport or Sport Plus are selected, the M550i shows its more aggressive side but without sacrificing the ride comfort that made it so effective in the first place. The steering sharpens with more effort, the suspension firms up, the gearbox shifts quicker and holds gears longer, the pedal response is needle-pricking sensitive and more importantly, the exhaust opens up and clears its throat. The F90 M5 is much louder with more excessive pops and burbles on overrun, but I can see how some might find that immature and excessive. The M550i by contrast offers a professional yet typical V8 soundtrack that doesn’t feel artificially synthesized.

In Sport mode, the force-fed V8 doesn’t feel turbocharged at all due to its free-revving nature – a signature BMW trait. There’s a tidal wave of torque the moment you step on the gas, and it never lets up until you need to shift. From there, the buttery smooth 8-speed takes over with a creaminess that few high-performance business sedans can muster. I actually prefer this 8-speed over the 7-speed DCT in the outgoing M5, which was lightning quick but lacked refinement and smoothness when cruising at lower speeds.

The M550i interior stands out as a comfortable yet familiar place to spend time in. The cabin amenities may not dazzle and sparkle like those in the equivalent E-Class AMG, or offer the same kind of technological wizardry as the Audi RS models, but it sticks to its tried-and-true methods of offering passenger connectivity and functionality. With eight shortcut buttons, a proven rotary dial, and a large touchscreen display, users are never left wanting. The seats are beyond comfortable with dual-adjustable backrests and airplane-like foldable headrests, and the rear seats, though admittedly tight for a mid-size sedan, are more than usable for the average-sized adult. 

Of course, the M5 is still the way to go if you’re searching for a no-compromise performance sedan. We’ve driven it multiple times on Portuguese roads and on our home turf, and while its everyday civility and spellbinding performance cast a large shadow on its rivals, I would still urge you to check out the M550i xDrive. It comes 80% of being an M5 but with a more mature demeanor, a less shouty exhaust, and is dripping in sleeper status material. That’s just my kind of 5 Series.