Despite the M at the front of its name, the BMW M550i is not a full-fledged M vehicle. Rather, it's the M Performance version of BMW's 5 Series sedan. Think of it as a step above a top-of-the-line 540i M Sport, but something that doesn't quite reach M5 levels of badassery.

But make no mistake, there's still plenty of M in this 550i. It's a great alternative for folks who don't want to pony up for the full M5 treatment.

M Performance

The M550i is one of many M Performance BMWs, along the lines of the X3 M40i, X4 M40i, M240i, M760i and so on. M Performance brings a lot of cosmetic upgrades to the already pretty 5 Series, including M accents on the large front air intakes, aluminum pedals, unique floor mats and a thicker-rimmed steering wheel.

What's most important, though, is the powertrain. The M550i gets BMW's twin-turbocharged 4.4-liter V8 engine with 456 horsepower and 480 pound-feet of torque. It also gets a stiffer chassis that lowers the car by almost half an inch compared to a standard 540i, a sports exhaust and larger, M Sport brakes.

There is an absolutely massive amount of power on tap here. It may not be an M5, but BMW says the M550i will sprint to 60 miles per hour in under 4 seconds, which is not only totally believable, but still damn quick.

Up in the mountains of Colorado, the M550i really wakes up when I put it into Sport Plus mode, the ZF-sourced eight-speed automatic transmission firing off quick shifts, holding gears through the entire rev range. The M550i willingly dives into the tight hairpins and decreasing-radius turns of the Rockies. If you enter a corner too quickly, dial in more to the steering and let the active all-wheel drive system move torque around to keep oversteer at bay.

In the car's default Comfort mode, the M550i provides a smooth, compliant ride -- perfect for a late-night trek on Colorado highways as snow starts to fall. The steering is lighter, the ride softer and the transmission less eager to shift with immediacy. It drives as beautifully as a 5 Series should. The inherent sportiness of the M Performance package does not ruin this car's daily-driving attributes.

A number of driver assist functions make it easy to use in daily commuting, too. Lane-keeping and traffic jam assist systems work together to steer the M550i without any input from the driver, and while this tech doesn't work on winding back roads, it's great for long stretches of highway with extensive, sweeping turns. Blind-spot warning works at speeds above 15 mph, and steering intervention kicks in above 40 mph. It's good safety tech, but wow, that intervention is strong.

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Comfy cozy

I love this test car's sumptuous Cognac Dakota (read: tan) leather interior, highlighted by contrasting blue stitching. There's shiny black trim on the dash, but it's tempered by open-pore wood and brushed aluminum pieces that look and feel awesome.

As a relatively large sedan, there is plenty of head- and legroom for both front and rear passengers and the trunk offers a generous 18.7 cubic feet of space. There's a pass-through for longer items, presumably skis, and the rear seats fold down as well for bulkier cargo.

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Good tech, for a price

BMW's iDrive infotainment system is served up on a large, 10.2-inch screen. It's easy to use, and can be operated either via touch, or with the rotary controller on the center console. Gesture control allows me to control audio volume or answer a phone call with some simple hand motions, but it doesn't work perfectly every time. Circling my right finger near the center stack is supposed to increase the volume, but most of the time, I found it more reliable to just use the mechanical knob.

While I like BMW iDrive just fine, I prefer to use Apple CarPlay. BMW offers it, but as a $300 option. Why would I pay a couple hundred bucks for smartphone mirroring that comes standard on much cheaper cars? This is nickel and diming at its worst.

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Options, options, options

BMW is known for offering myriad option packages and standalone add-ons, and the M550i is no different. There are seven different packages available, all ranging in price from $700 for the Parking Assist package, to $3,600 for the Dynamic Handling Package. My test car, with six of the seven packages selected, plus à la carte options like gesture control, CarPlay, night vision and an upgraded Bowers & Wilkins audio system, rings in at $88,985 including $995 for destination. That's a pretty big increase over the M550i's $72,100 base price.

For me, I'd definitely want the Dynamic Handling Package, mostly for the adaptive suspension. I'd also shell out $3,400 for the two Driving Assistance packages, which add the passive and active blind-spot and lane-keeping assist, as well as adaptive cruise control and forward collision warning. I'd even spend $300 on Apple CarPlay, begrudgingly.

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Stiff competition

Ze Germans know their luxury/sport sedans. Mercedes-Benz offers a similar formula in the form of the AMG E43, which costs about the same but is down 60 horsepower compared to the M550i. An Audi RS7 puts you into six-figure territory, but the less-powerful S6 sedan is about the same price as the BMW. You could look at a Cadillac CTS V-Sport, too, which is down on power, but also starts at $10,000 less than the BMW.

Of course, there's also BMW's own M5, which offers 600 horsepower, 553 pound-feet of torque, all-wheel drive that can become rear-wheel drive when asked and phenomenal handling. It comes at a price, though: $30,500 more than the M550i. I can't imagine absolutely having to have the M5. I'd rather have an M550i and a Mazda MX-5 Miata.

The M550i packs more than enough performance for public roads, and is comfortable enough to handle your commute with aplomb. It's not an M5, sure, but it's a less-expensive choice that doesn't sacrifice much in the way of comfort, tech or behind-the-wheel fun.