BMW M550i Tuned By Dinan is Luxury Land Missile

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Dinan BMW M550i is all about subtlety, at least, until you turn it on.

The BMW M550i is an odd car. I once described it as offering “75% of the BMW M5 experience for 75% of the price.” Not exactly massive praise. There is something a step off about the M550i, and it mainly falls to the name.

The BMW M5 is an iconic sports sedan, offering superb driving dynamics, a stout powertrain, and real, honest-to-goodness backseat room. This M550i represents a not-quite M car. BMW won’t say it outright, but the M550i is a stop gap performance model, designed to cover up the gap in M5 production as the manufacturer tinkered with new chassis codes and design elements. The new 2019 M5 rolls on a completely different chassis than this 2018 M550i.

If this sounds a bit confusing, and like something of a word jumble, that’s because it is. However, what a standard M550i may lack in attitude, or intention isn’t relevant today. Dinan BMW M550i xDrive Review

This M550i has been tuned by Dinan, and it is ready to kick the ass of any other M550i that tries to keep up.

Under the hood, the 4.4-liter, twin-turbocharged V8 remains largely the same as a standard car. There is an ECU upgrade tucked away along with the engine bay electrics. Under the car is a Dinan exhaust system. That’s it for power upgrades. Underwhelmed? Don’t be: that’s all it takes to boost the M550i’s output from 456 horsepower and 480 lb-ft of torque to a monstrous 606 horsepower, and 635 lb-ft of torque.


There is a certain joy to driving a very potent car, with ego-killing performance, and having no one be any the wiser about it.


Those pipes play a definitively V8 soundtrack, which sounds obvious, that is, until you compare it against the standard car. In terms of decibels, the Dinan exhaust isn’t massively louder than the original. However, it’s all in the tonality. The standard M550i exhaust note is…okay. It’s exists, but you could be forgiven for thinking it’s a six-cylinder-powered car rather than a V8. The Dinan pipes, when on the loud pedal, let the world know that eight cylinders are working with turbochargers to create magic and horsepower.

It’s time to drive

Cruising around town in the Dinan-tuned M550i is delightful. The Dinan suspension items lowering springs and modified bump stops  leave the ride no rougher than a standard car, while improving the aesthetic. The ride quality is taut, but never punishing. I could put some serious miles on this ride and be a very happy camper.

The Mediterranean Blue Metallic paint job is one of my all-time favorites. Depending on the lighting, it’s a subtle dark blue, a bold purple, or a near night sky black with blue tones. That said, apparently it is mostly the subtle dark blue because no one batted an eye at this big Bimmer. There is a certain joy to driving a very potent car, with ego-killing performance, and having no one be any the wiser about it.

Leave 8-speed automatic transmission in full-auto, and enjoy the dulcet, and seemingly distant rumble from the Dinan tailpipes, as your heart rate slowly lowers. The level of cabin isolation and serenity offered by the M550i makes for a relaxing drive.

Of course, being an excellent boulevardier means that Dinan has implemented their upgrades in a non-obtrusive way, which is nice. However, BMW sports sedans earn their chops on the winding road, so let’s go find one of those and see if the Dinan difference is there.

Move on to the next page to continue reading about the Dinan BMW M550i.

Jake Stumph is the Content Editor who runs 6SpeedOnline, and several other Internet Brands Automotive websites. He enjoys track days, drifting, and autocross, at least, when his cars are running right.

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