BMW M550i Tuned by Dinan: Luxury Land Speed Missile

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Dinan-tuned BMW M550i is all about subtlety, 606 horsepower worth of subtlety.

I want to let you in on a little secret of mine. I recently drove a BMW M550i xDrive. With 456 horsepower, and 480 lb-ft of torque emanating from the 4.4-liter, twin-turbocharged engine, it is no surprise that this is a very fast car. It is also, by all accounts, a rather nice place to be. The leather feels of good quality, the buttons and knobs all do what you expect they would, and the ride quality is comfortable enough to shuttle friends and family around with them being completely unaware that this thing can easily dispatch of some lesser sports cars. I should like this car. However, this not-quite-an-M5 BMW irks me.

It’s too joyless. A 456 HP anything should be fun, but the M550i just feels aloof. Ignore the bottom half of the accelerator pedal and this car could just as easily be badged 530i, I’d be none the wiser. The M550i, as it comes off the showroom floor, offers a dynamite engine that is waiting for the rest of the car to catch up.

Imagine my surprise when, just weeks after driving the M550i, Dinan rang me up and asked if I wanted to try their interpretation of the M550i, in the same color, no less. I was hesitant, then they emailed me a copy of the dyno sheet. 606 HP worth of persuasion later, and I was sitting in another Mediterranean Blue Metallic BMW M550i. Of course, this one features a matte black Dinan badge on the trunk.

Hold the phone, 606 horsepower?

Yup, and 635 lb-ft of torque, too. It’s a monster.

Despite the massive 150 horsepower, and 155 lb-ft of torque gain, the Dinan power upgrades are quite mild. A free-flowing exhaust (2,499.00) and custom ECU reflash ($1,799.00) is all it takes to see that massive power bump. Yes, really, that’s all it takes to spike an M550i’s power output by an extra 33%. I’d invest in just about anything that promised an immediate 33% bump in return, even if it was something odd like walnuts.

Speaking of nuts, and bolts, the list of physical hardware changes to this Dinan-tuned M550i is a short, and sweet, one. A set of lowering springs ($299.00) bring the ride height down and roll stiffness up a touch. Paired with those springs are revised bump stops ($149.00. All in, it’s a $4,746 package.

Then, there are the gorgeous set of Forgeline AR1 wheels, which are shod in a set of Michelin Pilot Sport 4S Summer tires. Dinan threw them on for style points (and they nailed it).


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