How this car would look is the easy part. Just take a look at the picture renderings below. Sexy? Sure, the car definitely would look good. The hard questions to answer are what would be under the hood. Just the same N55 motor with some more aggressive software? An M model without an M motor again? Would this really amount to anything more than an M235i with a tune and bodykit?
BMW could take that route and do the path of least resistance offering maximum profit. BimmerBoost will give them as much flack as humanly possible if they do. Let's say an M2 does come, wouldn't a motor designed to compete with the Mercedes-Benz CLA45 AMG M133 four-cylinder make more sense?
Then the problem of the N55 motor in the M235i outpowering a smaller four-cylinder in the aftermarket relatively easily arises. However, an M motor has never been about raw power. It is true that the N54 turbo six-cylinder in the 335i can make more power than the S65 V8 in the E92 M3 with an aftermarket tune. However, the more rewarding driving experience, response, and road course prowess is provided by the M3 V8.
With the original E30 M3 BMW designed the famous S14 four-cylinder despite having a six-cylinder already available for duty in the E30. The S14 motor provided a driving experience and placement in the chassis giving a level of balance as well as a lighter weight that could not be matched by the six cylinder E30 models. The E30 M3 was the best E30 3-Series offering the most exciting driving experience despite not having the largest motor.
BMW could repeat their history here and actually make a true spiritual successor to the E30 M3. Will they? Likely not, as chances are the M235i with some BMW Performance Parts will be where this all ends. It sure it interesting to think about what the M2 could potentially be though.