2021 BMW M340i

in Sedans
2021 MODEL
$54,700 - $56,700
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2021 BMW M340i Complete In-depth Review & Buying Guide

Updated on: October 14, 2020

Rishabh Mehra's image
Rishabh Mehra

Automotive Content Writer

A BMW badge is enough to guarantee class, quality, and performance. With the 2021 BMW M340i, this German Automobile manufacturer provides a route to relive the legacy of luxury and comfort all packed in a sporty sedan. The M340i is the most powerful 3 Series until the new M3 arrives. Under the hood, it is unmistakably a Bimmer as it is powered by a smooth yet utterly powerful straight-six engine producing 382 horsepower. As standard, the power flows to the rear wheels but AWD is optional. The pricing starts from $54,000 for the rear-driven M340i.

The 7thgeneration model of the BMW M340i has its work cut out with competitors like the Mercedes-AMG C43, Audi S4, and INFINITI Q50 Red Sport 400.

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Powerful and refined six-cylinder engine

Sporty yet fuel-efficient motor

Agile handling

Roomy on the inside


No manual transmission

What's New?

Expect to see Android Auto compatibility

Carry over model for 2021

Pictures & Videos

2021 BMW M340i Interior video


2021 BMW M340i in Polar White color
Polar White

Vehicle images are guides only and may not reflect the model's exact specifications/features– exact specifications/features should be confirmed with the seller.




Engine And Performance


Fuel Economy








Trims and Configurations


2021 BMW M340i Base


382 hp @ 5000 rpm
Premium unleaded
26 combined

$54,700 - $56,700

Style Prices MPG Engine Transmission Drivetrain Seats Colors
4dr Sedan (3.0L 6cyl Turbo 8A) Starting at $54,700 MSRP (22/26/30) 382 hp @ 5000 rpm, 3 L, Inline 6, premium unleaded
8-speed shiftable automatic rear wheel drive 5
xDrive 4dr Sedan AWD (3.0L 6cyl Turbo 8A) Starting at $56,700 MSRP (22/26/30) 382 hp @ 5000 rpm, 3 L, Inline 6, premium unleaded
8-speed shiftable automatic all wheel drive 5

Expert Review


Overall Rating

The BMW 3 series has always been a great sedan that offers an engaging driving experience thanks to a sporty chassis and a peppy motor under the hood. The new M340i takes the game up a notch or two. It’s not just a 3-series with a bigger and more potent motor, it has been fiddled with M-performance engineers who love to drive. 

The new B58 straight-six engine offers a bonkers performance so much so that the M340i now is as quick as the previous-gen M3. It gets bigger M-spec brakes, chassis strengthening and a sporty differential at the back to put all that power down on the tarmac. Stick it into comfort mode, and the souped-up 3-er transforms into a happy cruiser.

2021 BMW M340i Sedan Front 3 Quarter View
2021 BMW M340i Sedan Rear 3 Quarter View


Engine and Performance

Fuel Economy



2021 BMW M340i Features


The BMW M340i comes in only one trim which is luxurious and well-equipped. The drivetrains offered are Rear-Wheel Drive (RWD) and All-Wheel Drive (AWD). The powertrain is similar across both the variants with similar power output and features. Transmission duties are handled by a ZF 8-speed torque convertor. 


M340i Sedan





Key Features

Powered moon-roof


Navigation system


Auto-dimming rearview mirror


14-way power-adjustable front sport seats


3-zone automatic climate control


8.8-inch touchscreen infotainment system

The M340i starts at approx. $54,700 and carries guaranteed luxury and comfort. This German beauty comes equipped with a premium luxury sound system, smart device integration, and a variety of exterior color options that enhance the look even more. The BMW M340i is expected to carry forward the same package for the 2021 model year.

2021 BMW M340i Maintenance, Reliability and Warranty

BMW has a reputation of building good quality cars with sophisticated design and a decent reliability. With its strong chassis, safety features, and a perfectly built powertrain the M340i carries with itself a quantifiable amount of assurance. Regarded as the best in its class, the BMW M340i is ready to set the bar higher, yet again, with its latest offering.

The Ownership cost may slightly be towards the higher side as a BMW has expensive after-sales services but on a positive note the M340i does not ask for much and there is no vehicle in this class with such high-quality that provides an enjoyable ride experience. Moreover, all luxury sedans have similar expenses.

Overall, with unmatchable reliability and safety assurance and moderate ownership cost, the 2021 model stands above all as the most reasonable choice in this segment. The motor is particularly reliable and bulletproof and this is the reason why Toyota went ahead with putting BMW’s B58 turbocharged inline six engine in its GR Supra. Toyota expects its customers to go berzerk with aftermarket tuning and dial up the power meter to eleven. It's been a year since Supra has been on sale and people have extracted more than 1000 horsepower using stock internals which itself says a lot about the reliability of the powertrain. 


A number of friendly warranty packages make the M340i even more appealing. A complimentary maintenance service is offered for a period of 3 years or 36,000 miles, while corrosion warranty is valid for a period of 12 years and unlimited miles which makes the package look more interesting and only Jaguar has been able to give it a tough competition so far.



Limited Warranty

4 years/50,000miles; whichever is earlier

Powertrain Warranty

4 years/50,000miles; whichever is earlier

24-Hour Roadside Assistance

4years/ unlimited miles; whichever is earlier

Besides 24-hour roadside assistance for 4 years and unlimited miles, the Powertrain and limited warranty is offered for 4 years or 50,000 miles, whichever is earlier. The warranty package is more than sufficient and makes the M340i hard to resist. Mercedes on the other hand loses out to BMW as it offers no complimentary maintenance schedule for its Mercedes AMG C43.

Miles per Dollar

If you are looking for a sedan in this range, the BMW M340i will steal your heart in this segment as well because it offers the most fuel-efficient engine. The turbocharged straight six engine returns up to 22 mpg in the city and so the fuel cost ranges up to $1,800 for a year. The BMW M340i should cover 8 miles per dollar which is quite cheap considering the performance it has on offer.

2021 BMW M340i Buying Advice

Although the M340i is the sole trim that is offered, you can still choose between the RWD and AWD versions. The RWD version gives a pleasant and satisfactory performance but with a slight difference in the price, you can go for the AWD version which provides a more refined performance and allows you to enjoy the ride throughout the year. 

Is buying a used BMW M340i Sedan a good idea?

All BMW vehicles hold a comparatively good resale value because of the quality as well as the brand image which comes with a BMW. The M340i is counted amongst the BMWs with the most resale value so even after years of long drives, you can still feel the same strength and value. With a used M340i, you’ll lose out on some of the latest in-cabin tech and features but the performance quotient is always high with BMW cars. A well maintained and low mileage M340i can be a sweet deal.

2021 BMW M340i Engine and Performance


Under the hood of the 2021 M340i, you can see a 3.0L turbocharged Inline-6 engine with 8-speed automatic transmission which has the capability to churn out 382HP and 369lb-ft of torque. The performance is smooth and calm. The AWD version offered by BMW stands out as a better performer and companion for rides.

The Motor has power reserves all the time and it delivers every time you stomp on the gas pedal. The transmission shifts keenly to maintain an uninterrupted surge of power and torque. The sedan never feels handful or intimidating especially when coupled with the xDrive AWD system. It puts down all the power efficiently and maintains traction at all times. 

2021 BMW M340i Sedan Engine

Max power comes in at 5800rpm; however, the engine continues to rev until it hits the limiter set at 6500rpm. The sophisticated independent rear suspension feels refined and offers a predictable handling.


2021 BMW M340i 

2020 Mercedes-AMG C43

2020 Audi S4

2020 INFINITI Q50 Red Sport 400







3.0L Turbocharged Inline Six-Cylinder

3.0L Twin-Turbo V6

3.0L Turbocharged V6

3.0L Twin-Turbo V6







8-Speed Automatic

9-Speed AMG SPEEDSHIFT TCT Automatic

8-Speed Automatic Tiptronic

7-Speed Shiftable Automatic


382 hp @ 5,800 rpm

385 hp @ 6,100 rpm

349 hp @ 5,400 rpm

400 hp @ 6,400 rpm


369 lb-ft @ 1,800 rpm

384 lb-ft @ 2,500 rpm

369 lb-ft @ 1,370 rpm

350 lb-ft @ 1,600 rpm

The INFINITI Q50 is the most powerful contender as it churns out 400HP and 250lb-ft of torque. Even though the M340i will leave you satisfied with its performance, its rivals including the Mercedes AMG C43 offer slightly more power. 

2021 BMW M340i Sedan Acceleration and Braking Performance

Off the line, the acceleration is smooth and feels strong. There are different driving modes that can tune the engine response, throttle sensitivity and steering performance. The steering wheel is easy-to-handle and the chassis feels compact and chuckable around the twisties. In a straight line, the Bimmer can hit 60 mph in just 4.2 seconds which is quicker when compared with the previous-gen M3. 

2021 BMW M340i Sedan Engine Accelerate 0-60 MPH in 4.2 sec

The 13.7-inch front rotors and a well-managed thanks to a suite of electronic nannies. The ABS is perfectly calibrated and under heavy braking the ESC maintains the ride and the M340i remains planted and feels sure-footed. 


2021 BMW M340i 

2020 Mercedes-AMG C43

2020 Audi S4

2020 INFINITI Q50 Red Sport 400

0-60 (seconds)





Quarter-Mile (seconds)





Top Speed (MPH)





60-0 (feet)





BMW M340i is the quickest to cover the quarter-mile in 12.3-seconds whereas the 0-60mph sprint time is not the best but still good enough. On the other hand, the Mercedes Benz C43 has the quickest 0-60mph time and the slowest quarter-mile timing of 14.1-seconds. With a 4.3-seconds sprint time to reach 0-60mph, the Audi S4 performs moderately well.

2021 BMW M340i Fuel Economy


The M340i proves itself to be the numero uno choice once again as it is the most fuel-efficient vehicle in its class. The fuel mileage for the 2021 BMW is still to be known while the current model is capable of giving fuel specs of 22mpg in the city and 30mpg on the highway with a maximum fuel capacity of 15.6-gallons.


2021 BMW M340i 

2020 Mercedes-AMG C43

2020 Audi S4

2020 INFINITI Q50 Red Sport 400

MPG (City)





MPG (Highway)





MPG (Combined)





Fuel Tank Capacity (Gallons)

15.6 gallons

17.4 gallons

15.2 gallons

20.0 gallons

Range (City/Highway/Combined; Miles)





INFINITI Q50 which has the most powerful engine in this section fails to give a sense of real competition to its rivals in this segment with average fuel figures of 19mpg in the city and 26mpg on the highway and even the C43 shows similar results. Audi S4 comes forth as a tough contender to the M340i.

2021 BMW M340i Interior

The cabin of the M340i is all luxury, with top-quality material and oodles of tech.. With a 5-seating capacity, the sedan manages to provide equal comfort for the rear seats as well, with heated seats and rear AC controls. The SensaTec faux-leather upholstery feels soft to touch and is used all over the cabin which enhances the look and feel of the cockpit. 

2021 BMW M340i Sedan Cockpit Area

The 3-zone automatic climate control with 14-way power-adjustable front sports seats makes the interior a great place to spend time in. The new 7th-gen 3-Series has grown in size and is now as big as E39 5 Series which means that even though it sits in the compact sedan segment, the cabin offers plenty of space on the inside. 


2021 BMW M340i 

2020 Mercedes-AMG C43

2020 Audi S4

2020 INFINITI Q50 Red Sport 400

Seating Capacity





Front (Headroom/Shoulder Room/Legroom; inches)





Rear (Headroom/Shoulder Room/Legroom; inches)





Trunk capacity of 17 cubic feet is offered in the M340i making it the most spacious cargo and the most practical compact sedan. The Q50 manages to give a measly 13.5 cubic feet of space which is not even close to the M340i. Sufficient space is provided for nifty objects in the cabin as well. 

You can have a ton of fun with it as a typical sports car and furthermore appreciate the functionality it provides like that of a 4-door family car. The upcoming model is expected to follow the same recipe. 

Infotainment system

Like all the other segments, the M340i performs well in this segment as well by offering great quality and convenience. The M340i carries an 8.8-inch touchscreen powered by the ubiquitous yet one of the best iDrive infotainment systems which is easy-to-use and pairs up with a 10-speaker audio system. Voice and gesture control are a major plus point.

2021 BMW M340i Sedan Infotainment System

A plethora of features are offered in the BMW including Bluetooth Connectivity, a Navigation system, Apple CarPlay, and an optional 16-speaker Harman Kardon surround-sound system. We hope that the 2021 model will bring us more entertainment features and not to forget, Android Auto Connectivity.

2021 BMW M340i Sedan cockpit area
2021 BMW M340i Sedan Interior Image
2021 BMW M340i Sedan steering wheel
2021 BMW M340i Sedan Interior Image
2021 BMW M340i Sedan front seats
2021 BMW M340i Sedan Interior Image
2021 BMW M340i Sedan front seats
2021 BMW M340i Sedan Interior Image
2021 BMW M340i Sedan shift knob
2021 BMW M340i Sedan Interior Image
2021 BMW M340i Sedan rear seats
2021 BMW M340i Sedan Interior Image

2021 BMW M340i Exterior


The 2021 BMW M340i has one of the better looking BMW signature kidney grille that we have seen lately, with perfectly placed slotting for improved streamlined efficiency. The new BMW M340i has perfect proportions now. The dimensions and numbers have ballooned up, especially the curb weight of 3800 pounds but in terms of size it feels just perfect. The chart-topping wheelbase improves the room on the inside, promising solace and comfort along with an exemplary performance. 

2021 BMW M340i Sedan 3 Quarter View

The M340i gets a set of full LED headlights and taillights, the traditional Hofmeister kink on the C-column, and a couple of twin round chrome exhaust tips and a low and wide stance at the back polished off in chrome. A set 18-inch M-spec alloy wheels are covered in all-season rubber. The palette incorporates standard choices like Alpine White, Jet Black, Sunset Orange, and Melbourne Red.


2021 BMW M340i 

2020 Mercedes-AMG C43

2020 Audi S4

2020 INFINITI Q50 Red Sport 400

Curb Weight (lbs)





Length (inches)





Width (inches)





Height (inches)





Ground Clearance (inches)





Wheelbase (inches)





The INFINITI Q50 is the heaviest with 3993lbs of curb weight whereas the Audi S4 offers the highest ground clearance of 5.0-inch making the S4 desirable for travel on slightly bumpy roads. The BMW M340i and the INFINITI Q50 offer similar wheelbase and width.

2021 BMW M340i Sedan three quarter view
2021 BMW M340i Sedan rear three quarter view
2021 BMW M340i Sedan three quarter view
2021 BMW M340i Sedan rear three quarter view
2021 BMW M340i Sedan rear three quarter view

2021 BMW M340i Safety


Although the 2021 BMW M340i is yet to receive safety ratings from the NHTSA and IIHS, the 2020 model was appraised as the top safety pick from the IIHS. There is a long list of safety features that are offered but most of them are provided in packages. Some of the key features include a panic alarm, electronic stability, DRLs, blind-spot monitoring, and Frontal-collision warning with City Collision Mitigation.

2021 BMW M340i Competition

2021 BMW M340i vs 2020 Mercedes-AMG C43

Mercedes Benz C43 stands as one of the toughest competitors of the M340i. Although the C43 comes equipped with a more powerful engine and better acceleration, the high price it quotes makes it a less practical choice as the M340i comes with the most fuel-efficient engine, a spacious trunk area as well as more ground clearance.

2020 Mercedes-AMG C43

2021 BMW M340i vs 2020 Audi S4

Audi S4 is clearly more luxurious and classier but it has managed to excel in terms of looks and comfort only, as the performance is not energetic and the weakness under the hood can be felt out on the road. If you are looking for a strong companion then the BMW M340i is a perfect choice, else the Audi S4 comes with enough luxury and comfort features to make it valuable.

2020 Audi S4

2021 BMW M340i vs 2020 INFINITI Q50 Red Sport 400

A powerful engine at a low price is a plus point for the INFINITI Q50 but the M340i proves to be of more worth with its fuel-efficient engine, quick acceleration, spacious seating as well as impressive trunk capacity. To conclude, the M340i clearly nudges out the Q50 and proves itself as a winner.

2020 INFINITI Q50 Red Sport 400

2021 BMW M340i Final Verdict

The BMW M340i is a combination of style and power. The versatile sedan is successful in wooing everyone’s heart with a spacious interior, commendable fuel efficiency, stylish exterior looks, a plethora of entertainment features, and uber smooth handling. 

It's a massively engaging vehicle that will make you take the long route home from work and can be lovely for smooth drives in the city. The capacity to fill the role of a sporty b-road carver and consistent cruiser makes it a sweet spot fulfilling sports vehicle.