One of the most significant models in BMW’s lineup, the M3, is due for renewal, and as a result prototypes for its replacement have been spotted all over Europe and in the U.S. Once again there will be sedan, coupe and convertible variants, but where previous models were all badged M3s, the new versions will see a major shakeup concerning their nomenclature.

Essentially, the next generation of the two-door M3 models will migrate to the M4 name, while the M3 sedan’s name won’t change. In line with the new naming practice, we’ve already seen the replacement for the 3-Series Coupe adopt a 4-Series name. The reason behind the move is part of BMW’s plans to further differentiate its sedan and coupe models.

But whatever name you use for the latest M model, it's likely to be just as notorious for being a capable track weapon as previous versions. The M4 is expected to forgo the 4.0-liter V-8 of the M3 Coupe it’s replacing in favor of a turbocharged straight-six engine.

Alleged VIN information uncovered on the web indicates the M4 will get its power from a 3.0-liter inline six-cylinder engine coded S55. That makes it sound very much like a high-performance derivative of the N55, BMW's twin-scroll turbo engine used in the 335i among others, and we’ve heard BMW M will no longer have completely unique engines going forward.

Nevertheless, performance should be strong thanks to an expected 416-horsepower for the new M4. That may be similar to the outgoing M3’s output but we suspect more torque. Torque is good.

What else can you expect of the M4, despite the lack of definite information? Like the latest 4-Series, with which it will share a platform, we expect a good deal of lightening through more advanced materials, improved interior comfort and design, and--thankfully--improved gas mileage over the sweet-sounding, high-revving, but very thirsty V-8 of its predecessor.

To enhance traction, the M4 is thought to also receive an electronically controlled differential capable of delivering 100-percent lockup under the right conditions as well as torque vectoring between the rear wheels. Other signature M elements such as a carbon fiber roof, uprated brakes and quad-exhaust tips will also feature.

We'll keep you posted with further details, images, and videos as the car continues development and testing. Look for the debut of the new BMW M4 early next year.

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