Thursday, July 18, 2024
Comparison2020 BMW X3 M vs Mercedes-AMG GLC 63 S Spec Comparison

2020 BMW X3 M vs Mercedes-AMG GLC 63 S Spec Comparison

BMW introduced its first-ever real M model for the X3 and X4 lineups last night. Their main competitor will be another high-performance compact SUV from Germany, the Mercedes-AMG GLC 63 S.

What do we mean by a “real” M model? Simply that the 2020 BMW X3 M is above and beyond anything the BMW X3 M40i can offer. It has at minimum 118 extra horsepower, it will be louder, more agressive looking with the usual real M quad exhaust in the back and will be generally sportier and angrier.

The X3 M40i is nice and balanced. The 2020 BMW X3 M is mean and won’t really care if it’s stiff suspension jolts your morning coffee into your nostrils. It’s direct competitor is another mean-spirited yet so desirable monster of a compact SUV from Germany, the 2019 Mercedes-AMG GLC 63 S.

The X3 M will also get some heat from the Porsche Macan Turbo and to a lesser degree the Alfa Romeo Stelvio Quadrifoglio. We say a lesser degree here not because the Alfa can’t hang with these other three performance compact SUVs, it’s just that nobody is buying it.

In any case, we thought it would be interesting to compare the specs we have on the 2020 BMW X3 M with the Mercedes-AMG GLC 63 S. If you guys like it, we may even compare it with the Porsche Macan Turbo.

We don’t have all the details yet on the new X3 M and X4 M, but we have enough to compare it with the GLC 63 S on the basis of performance on paper. We can even compare efficiency. As for interior space, well the current BMW X3 and Mercedes-AMG feature roughly the same level of versatility. You can expect the same in the high-performance versions.

2020 BMW X3 M
2020 BMW X3 M | Photo: BMW
Mercedes-AMG GLC 63 S
Mercedes-AMG GLC 63 S 4MATIC+ | Photo: Mercedes-AMG


The new 2020 X3 M will offer two engine options while the AMG GLC 63 S offers just one. If you’re hoping to tell us that the GLC 43 is a second engine option, we’d refer you to the BMW X3 M40i we talked about previously.

Powering the “base” X3 M will be a twin-turbo straight-six 3.0-liter engine with 473 horsepower and 442 pound-feet of torque. If you really want to go bonkers, tick the box for the BMW X3 M Competition which gets 503 horsepower with the same amount of torque.

Is that good enough to outshine the Mercedes-AMG GLC 63 S? Nope. The beast from Stuttgart develops 503 horsepower and 516 pound-feet of torque out of the gate.

Actual Power

The AMG GLC 63 S has more power on paper than the 2020 BMW X3 M, but is it faster?. Early reports suggest so. BMW tells us that the X3 M will reach 100 km/h in 4.1 seconds with the Competition version, and 4.2 seconds in the “normal” X3 M. That’s good enough to beat a Macan Turbo and Alfa Romeo Stelvio Quadrifoglio to the finish line, but it won’t outpace the GLC 63 S.

The folks at Mercedes-AMG have a way of getting to 100 km/h really, really fast. Very few AMG models take more than 4.0 seconds to reach the benchmark, and the GLC 63 S is no exception. 3.8 seconds is all that’s needed.

Now, going fast in a straight line is one thing, but most would agree that it’s what you do on a track that really matters. The 2020 BMW X3 M will pack some pretty advanced tech designed to do just that with the Active M Differential, xDrive all-wheel drive with two AWD modes and a rear bias, and an M Dynamic Mode which gives the driver some leeway before the stability control system intervenes. You can also shut that sucker off.

The Mercedes-AMG GLC 63 S also has some pretty dynamic driving modes and a performance-oriented 4Matic all-wheel drive system, so the only way we’ll truly find out how they compare on a winding road is to test them some time later this year.

2020 BMW X3 M
2020 BMW X3 M | Photo: BMW
2019 Mercedes-AMG GLC 63 S
Mercedes-AMG GLC 63 S 4MATIC+ | Photo: Mercedes-AMG


We finish with an efficiency comparison. The 2020 BMW X3 M promises an average fuel economy rating of 10.5 liters per 100 kilometers. Hard to believe at first but we averaged under 11 liters per 100 kilometers in a BMW M3 Competition last summer, and under 10.0 liters per 100 kilometers in a BMW M2.

BMW has a knack for making their high-performance M models efficient and we believe their numbers for the X3 M. The Mercedes-AMG GLC 63 S is like every other AMG model. You can get decent fuel economy but only if you’re really, really smooth on the accelerator. You don’t need to be as careful with BMW M models. The average posted fuel consumption rating of the GLC 63 S is 10.7 liters per 100 kilometers.

So although most won’t care, the BMW X3 M will likely prove to be the most fuel-efficient of the lot.

2020 BMW X3 M Images Gallery

2019 Mercedes-AMG GLC 63 S Images Gallery


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Charles Jolicoeur
Charles Jolicoeur
Charles Jolicoeur was studying to be a CPA when he decided to drop everything and launch a car website in 2012. Don't ask. The journey has been an interesting one, but today he has co-founded and manages 8 websites including and as General Manager of NetMedia360. He also sits on the board of the Automotive Journalists Association of Canada. Send me an email


  1. My local MB dealer tells me I can not purchase a GLC 63 S as shown in your photos. He says I can have a GLC 63 S Coupe, which don’t like the look. Do you know why ?
    I am in Texas

    • It may be an availability issue. Maybe that’s all they have in stock. Depending on where you live in Texas, I’d send an email to other dealers. If you are willing to drive a few hours and can get one at another dealership, it may be worth it. You can also do a search on and see if they have models available at other dealerships in your region.

  2. To say the Alfa Stelvio Quad is not competitive is an oversight. It set the class standard, and because it simply should not be considered out of hand because it doesnt sell, does not make a vehicle bad. Nay, it prolly will remain the best drving HP SUV.


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