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The BMW M550i xDrive is 90% of the car the M5 is, and in some ways, it's actually better. The M550i offers strong V8 power and a long list of tech and creature comforts. What it lacks in outright track-attack ferocity it more than makes up for with greater overall balance and a much nicer ride quality. Given the choice, I'd pick the M550i as my daily driver.
The M550i uses BMW's twin-turbo 4.4-liter V8, with 523 horsepower and 553 pound-feet of torque running through an 8-speed automatic transmission. All told, the all-wheel-drive M550i can accelerate to 60 mph in just 3.6 seconds, which means it's quicker than its key rivals, the Audi S6 and Mercedes-AMG E53, both of which use more sedate six-cylinder engines. The BMW even comes with a proper launch control function, which I'm sure most people will never use.
Yes, the M5 uses a tweaked version of the same V8 engine, and yes, it makes as much as 617 hp in Competition guise. But the torque output is the same for the M550i, M5 and M5 Comp, and that quick-release turbocharged thrust is what you'll rely on most while pulling away from stoplights and merging onto the highway. The base M5 is 0.4 seconds quicker to 60 mph than the M550i, and that's not a disparity you'll notice 99% of the time, if ever.
The M550i uses BMW's Steptronic Sport automatic transmission, which is kind of a best-of-both-worlds gearbox. It shifts with the quickness of a dual-clutch transmission but has a torque converter, which makes it smoother at low speeds and when engaging first gear. The gearbox also works with the M550i's standard navigation system and optional adaptive cruise control to predictively downshift shift for corners or slower cars ahead of you, all based on information the various systems pick up. Metal, steering wheel-mounted paddle shifters let you manage your own shifts if you want, but this is yet another case where the transmission is smarter than I am. I'm perfectly happy to let it do its own thing.
I won't discount the M5's ability to hustle around a race course, but I also refuse to believe that anything more than a tin percentage of M5 buyers actually take their cars to the track. The tradeoff for the M5's sharp reflexes is an often punishing city and highway ride quality, even with the adaptive dampers set to Comfort.
The M550i, on the other hand, is far better balanced for everyday driving. Put the M550i into its Sport or Sport Plus settings and it's got ample poise on a good winding road. The standard sport rear differential keeps the rear end talking while the xDrive all-wheel-drive system moves power where it's needed most. M Sport brakes offer a lot of stopping power and they're easy to modulate. Meanwhile the Bridgestone Potenza tires are nice and grippy. My only beef is that the steering, while appropriately hefty, is totally numb. Same goes for the M5, though; this unfortunate steering characteristic plagues most new BMWs.
Leave the M550i in its Comfort or Adaptive settings and the dampers soften up just enough to smooth out small to medium road impacts while still delivering a controlled and composed ride, even when fitted with my test car's 20-inch wheels (19s are standard). Admittedly, you need to option the $3,600 Dynamic Handling Package to get the adaptive M suspension and active roll stabilization, but it's money well spent if you want to party.
Obviously, no V8-powered BMW is going to be frugal, and the EPA says the 2021 M550i xDrive should return 17 miles per gallon in the city, 25 mpg highway and 20 mpg combined. If that's an issue, I highly recommend checking out the 540i, which offers a turbocharged straight-six with mild-hybrid boost, and will easily beat 30 mpg on the highway.
The M550i gets a number of updates for 2021 that you'll find on other 5 Series models, including new headlights and taillights and a few updated interior trimmings. You could certainly criticize the 5 Series for being on the more sedate side of attractive, especially when compared to cars like the Genesis G80 3.5T or Mercedes-AMG E53. But I like the M550i, especially in this rich shade of Aventurin Red ($1,950) which looks slightly more red or purple depending on lighting. Personally, I like to call it Chillable Red.
The 5's interior is nice, but again, boring. There are only a few cheap bits of plastic to speak of, but they're on surfaces you won't touch most of the time. Everything else inside the cabin is great, from the soft leather seats to the attractive metal inlays to my test car's optional ceramic controls. It's ultra quiet in here, too, making the M550i a great car for day-to-day commuting.
The M550i comes standard with the 5 Series' full multimedia tech roster, starring BMW's iDrive 7.0 software. A 12.3-inch digital instrument cluster displays all sorts of relevant vehicle data, while a second 12.3-inch touchscreen handles the heavy lifting atop the dashboard. Touching the screen is the easiest way to operate this tech, though you can still use the rotary knob on the center console or work via voice commands. BMW's stupid gesture controls are part of the $2,150 Executive Package and can thankfully be turned off. Side note: I do think it's hilarious that, if you turn up the radio volume via the steering wheel button or tuning knob while the gesture controls are activated, a little display comes up on the screen showing you the hand motion you could be making. It's like the car's subtle way of reminding you that you aren't using a function in the newest and most interesting way. How German.
Personally, I prefer to use the wireless Apple CarPlay interface, which is standard, along with Android Auto. Wireless charging comes as part of the aforementioned Executive Package, as does a head-up display. You can also spec a bangin' Bowers & Wilkins sound system for an extra $3,400, if that's your jam. A surround-view camera and park distance control are bundled into the $800 Parking Assistance Package and advanced driving aids such as lane-keeping assist and blind-spot monitoring are part of the $1,700 Driving Assistance Plus pack. The latter also adds BMW's Extended Traffic Jam Assistant, which allows for limited amounts of steering assist on select roads below 40 mph.
A 2021 BMW M550i xDrive starts at $77,795 including $995 for destination, and a loaded example like the one you see here costs just under $94,000. That's a lot of money, but don't forget, you can't get into an M5 for anything less than $104,495. Unless you truly need the M5's slight bump in power and prowess, I say stick with the M550i and enjoy a much more livable -- and affordable -- package.