It’s no secret that BMW is working on a new M3 sedan, as well as a new M4 coupe and convertible. We’ve shown you spy shots and spy video of various cars in testing, but the market introduction of the new M offerings is still over a year away.

Britain’s Car magazine recently published an update on what it believes the next M3 will be like, and enthusiasts the world over hope the publication’s intelligence is correct. If it is, the next M3 will be more conservatively styled, lighter, faster and even more capable on track.

We know the current M3’s V-8 will be kicked to the curb, a victim of ever-tightening fuel economy and emission requirements. In its place will be a new twin-turbo 3.0-liter in-line six, based on the B58 engine family. In standard M3 and M4 guise, expect to see an output of 444 horsepower, which should deliver a 0-100 km/h (62 mph) time of 4.5 seconds.

The new engine is described as “highly tunable” as well, and word is that 500 horsepower can be had with just an ECU reflash. That likely means that BMW will offer special editions of its new M cars with a significant bump in horsepower.

As for styling, expect even more refinement than on current M3 models. The M versions will be lower and wider than their 3 and 4 Series counterparts, and 19-inch wheels will help to create a distinctive stance. Carbon fiber components, such as the roof, will be left unpainted, and other styling tricks will include blue brake calipers and graphite mirror caps.

Carbon ceramic brakes will also be offered on M3 and M4 models, likely at a (significant) up-charge. To let others know they won’t be out-braking you into corners, cars fitted with the carbon ceramic rotors will also get gold-painted brake calipers.

Word is that both a manual six-speed transmission and a seven-speed, dual-clutch automated manual gearbox will be offered. The electronically-controlled M differential will return in the new M3 and M4, giving the new cars the same sure-footed traction as the models they replace.

Look for BMW to trim weight wherever possible, too, and word is that the next M3 could come in below 1,500 kilograms (3,300 pounds), which is some 95 kilograms (209 pounds) lighter than a current BMW 335i sedan.

As for the “when” part, expect BMW to show a near-production “concept” M3 this fall, likely at the Frankfurt Auto Show. The production version should debut at Geneva in 2014, with European sales beginning in the summer of 2014.