The new BMW 4-Series will soon get the M treatment.

BMW is giving us a sneak peek at two of its new M pocket rockets with the first official images of the new 2015 M3 and M4 models.

Set to make their formal debuts at next month’s North American International Auto Show in Detroit, the two M cars will deliver more power and improved performance, BMW claims, even while they lose mass compared to the old M3 sedan and coupe models they’re meant to replace.

It will mark the first-ever M4, in fact, following the Bavarian makers decision to split off the coupe and convertible models as part of a new naming strategy. Going forward, odd numbers, like the familiar 3-Series, will be reserved for sedans, with coupes and cabriolets getting even designations, ala the M4 and 4-Series.

The 2015 remake will be the 4th-generation M3.

But they will continue to share much of the same underlying technology, notably including a new TwinPower 3.0-liter inline-six engine that now makes 425 horsepower and a searing 406 pound-feet of torque.  The M3 and M4 models will both be offered with an option of either a 6-speed manual gearbox or a 7-speed double-clutch transmission.  The manual option now will feature throttle blipping to ensure revs are properly matched while shifting.

“The engine is the heart of every M model, and the new turbocharged six-cylinder unit fitted in the two new cars combines the virtues of a high-revving naturally aspirated unit with the strengths of turbocharger technology,” says Friedrich Nitschke, president of BMW M’s group in a statement.

(BMW and Mini will share a new 3-cylinder engine. Click Here to find out more.)

For those who think they can outperform the DCT, they might need to think twice considering it’s rated at delivering 0 to 60 times of just 3.9 seconds – compared with 4.1 seconds for the stick.

The return to an inline-six layout should be good news for BMW traditionalists.  It’s an engine design that has long been considered the soul of the brand.

BMW returns to an inline-six for the new M3 and M4.

But there are plenty of other intriguing new features on the 2015 BMW M3 and M4 models, which are set to go on sale next summer.

For one thing, the new M cars make extensive use of lightweight materials such as aluminum and carbon-fiber-reinforced plastic to not only shave 22 pounds off the mass of the new models when compared to the outgoing M3 coupe and sedan, but also to improve weight balance.  A CFRP roof helps put the center of gravity closer to the ground.

Other new features include larger air intakes and the new Air Curtains which help improve airflow around the front wheels, traditionally a “dirty” area of the car from an aerodynamic standpoint. The various aero improvements not only improve performance but also raise fuel economy while helping achieve better cooling, says BMW.

While the maker has yet to release formal EPA numbers, it promises that the updated M3 and M4 pair will deliver a full 25% improvement in both emissions and fuel economy.  Considering the most recent version made 14 mpg City and 20 Highway, that’s a significant improvement.

(BMW Updates 5-Series GT, reveals Concept X4. Click Here for a closer look.)

Inside the new 2015 BMW M3.

The 2015 BMW M3 and M4 models will adopt a new, lightweight aluminum suspension. The performance cars also will migrate to a new electric power steering system, here with three driver-selectable modes.

The well-equipped interior will feature such distinctive M niceties, notes the BMW press release, as “M door sill finishers, an M driver’s footrest, M gearshift lever, M-design circular instruments with white graphics, M leather steering wheel with chrome trim, color contrast stitching and electroplated-look shift paddles” with cars equipped with the DCT transmission.

The 2015 remake will be the fourth-generation BMW M3 since the performance car was first introduced in 1985.

(For more on the all-new BMW 4-Series, Click Here.)