The 2021 BMW M3 CS is an upcoming, higher performance version of the company's four-door sedan. A successor to the F80-generation M3 CS that BMW produced in 2018, the 2021 M3 CS will boast similar upgrades over the current M3. It will feature a more powerful engine, a range of aero-enhancing features on the outside, some exclusive trim on the inside, and it will be built in limited numbers. Find out what will set it apart from the current M3 in the speculative review below.

Exterior

The prototype spotted on public roads is camouflaged nose to rear so we can't see much, but the upcoming M3 CS should be similar to its predecessor as far as extra features go. The new M3 CS will retain the M3's massive and controversial front grille, but the fascia will look a bit different thanks to a revised bumper. It should include bigger intakes in the center and to the sides, which will enhance engine and brake cooling, as well as a larger front splitter, likely made from exposed carbon-fiber. The M3 CS should also feature a new engine hood made from carbon-fiber-reinforced plastic. It will probably include a big bulge in the center for a more aggressive look.

The profile will probably remain the same save for a new set of light-alloy wheels, likely in an exclusive color, and a lack of chrome trim thanks to the standard Shadow Line package. In addition to black window trim, the M3 CS will also feature black front bumper vents, black door handles, and black mirror caps. The latter should also be available in carbon-fiber finish. The M3 CS could also sit a tad lower than the regular M3, but you probably won't notice it.

The upcoming M3 CS will look very similar to the M3 Competition around back. However, BMW will probably replace the small black spoiler with a Gurney-type element in carbon-fiber. If you want a big wing, you're better off waiting for the more hardcore GTS model. The CS badge will also bring a CFRP diffuser and stainless steel exhaust pipes.

Expect the M3 CS to be offered with at least one exclusive color, but BMW may have other surprises in store for the beefed-up M3.

Interior

It will feature the familiar two-tier dashboard with the big digital display in the center stack plus A/C vents and controls below. You'll also find a big digital instrument cluster behind the sporty steering wheel and a wide center console that hosts the gearbox interface and a storage area.

The M3 is already fitted with leather and Alcantara as standard and the CS model will retain those features. However, BMW will replace the regular hide with Merino leather. If you like livelier interiors, the M3 CS might disappoint you as it will most likely be almost completely black. But just like the old CS, the new sedan could feature lettering and stitching in lighter colors.

The M Sports seats will be wrapped in both leather and Alcantara and you will probably have the option to go with a two-tone finish. But don't expect BMW to offer flashy hues, as it will probably combine black with light gray or it's already familiar Silverstone finish (gray with silver accents). The "M3 CS" lettering on the door sills will further help this performance sedan stand out from the M3 pack.

While the GTS is a stripped-out M3, the CS will retain the everyday practicality of the regular sedan, so it will be fitted with all the convenience features. Tech-wise, it will come with BMW's Live Cockpit Professional infotainment system as standard. It includes cloud-based navigation, maps, the Intelligent Personal Assistant, all accessible through the 10.25-inch display in the center stack. The digital instrument cluster is larger at 12.3 inches, and it will include a few extras, mostly performance-related.

You'll be able to order ventilation for the front seats, but also lighter carbon-fiber bucket seats with removable head restraints for track driving. The three-zone automatic climate control and the hi-fi audio system should remain standard. The M3 CS won't have a roll cage. That's another feature you'll have to wait the M3 GTS model for.

Drivetrain

The previous M3 CS was slightly more powerful than the regular M3. Specifically, while the old M3 came with 425 horsepower and 406 pound-feet of torque, the M3 CS arrived with 453 horses and 443 pound-feet. That was a 28-horsepower and 37-pound-foot increase. The new M3 CS could benefit from a similar increase, but the current M3 is available in two states of tune, with the range-topping M3 Competition delivering more than 500 horsepower.

My guess is that the CS will be an upgrade to the M3 Competition. The latter packs 503 horsepower and 479 pound-feet of torque, so the M3 CS could have around 530 horsepower and 500 pound-feet of twist at its disposal. Since it will be based on the M3 Competition, it won't be available with the manual gearbox offered in the base M3. But that wouldn't be an issue since the old M3 CS was also a DCT-only model.

How quick will it be? Well, the M3 Competition hits 60 mph in 3.8 seconds. The extra oomph from the 3.0-liter inline-six should enable the M3 CS to get to the same benchmark in 3.6 clicks. This rating would make it a tenth-second quicker than its predecessor. Top speed should also be higher than the regular 155 mph. The M3 CS will most likely come standard with the M Driver's Package, which increases top speed at 180 mph. That's an extra six mph compared to the previous BMW M3 CS.

The beefed-up sedan should also feature a higher revving engine and a retuned chassis and tech. The package should include a revised exhaust system with lower back-pressure, an adaptive suspension system, and an active M differential. It should also employ more rigid axles and revised struts, grippier tires of the Michelin Pilot variety, and carbon-ceramic brakes. The latter could be optional though.

The M3 CS could brake cover as the fastest Bimmer on the Nurburgring Nordschleife. The old M4 CS lapped the "Green Hell" in 7:38 minutes and it's safe to assume that the more advanced M3 CS will be at least 10 seconds quicker. As of January 2021, the M4 GTS is the quickest BMW on the German track with a 7:27.88-minute lap.

How much will the BMW M3 CS cost?

It's obviously too early to talk about prices at this point, but it's safe to assume that the CS will become the most expensive 3 Series model when it comes out (and until M3 GTS arrives). It will thus cost more than the M3 Competition, priced from $72,800 as of January 2021.

The previous M3 CS was priced from $98,250, so the upcoming Club Sport model could come in at a little over $100,000 before options.

Will the BMW M3 CS be better than the Mercedes-AMG C63 S?

The AMG C63 S is the range-topping C-Class model right now and it packs a solid punch thanks to a twin-turbo, 4.0-liter V-8 engine rated at 503 horsepower and 516 pound-feet of torque. With a sprint to 60 mph of only 3.8 seconds, the AMG C63 S wouldn't be notably slower either. However, the Merc doesn't benefit from all the bells and whistles that come with BMW's "CS" badge. Unless the German release some sort of track-oriented model, the AMG C63 S remains a solid competitor for the M3 Competition, but a mild option compared to the upcoming CS. It's notably more affordable though, as it comes in at $76,200.

Read our full story on the Mercedes-AMG C63 S.

Will the BMW M3 CS be better than the Cadillac CT5-V Blackwing?

The CT5-V Blackwing is also a model from the future, but it will arrive in the first months of 2021. And unlike the AMG C63 S, it will be well-suited to take on the M3 CS. A beefed-up version of the existing CT5-V, the Black will boast numerous exclusive features, including carbon-fiber seats with bookmatched design and advanced aerodynamics. What's more, it will be powered by a massive 6.2-liter V-8 engine that will generate around 600 horsepower, if not more. On the performance front, the CT5-V Blackwing is expected to trump the M3 CS and possibly any upcoming version of the German sedan. The good news is that the Blackwing might be notably more affordable than the M3 CS.

Conclusion

Not only it adds more oomph and a track-oriented appearance to the performance sedan, but it also bridges the gap between the M3 Competition and the upcoming M3 GTS, a more radical four-door developed with track performance in mind. The M3's looks might still be controversial due to the front grille, but the CS will be a cool sedan that won't have competition from Mercedes-Benz and Audi. But it remains to be seen if it will give the upcoming Cadillac CT5-V Blackwing a run for its money.