Well, prototypes of the two German toys recently crossed paths while out testing on the Nordschleife. As you'll notice in the piece of footage at the bottom of the page, the M car was the one that chased the spiced-up Shooting Brake. And while fans of the latter will cry that an even more potent model is coming (think: the CLA 45 or CLA 50), the brief Ring moment we have here is simply a form of enterntainment and not intended to serve as a comparo.
However, while the already-unveiled Mercedes-AMG CLA 35 "sedan" (this is more of a four-door coup), with its 400 Nm/295 lb-ft and its seven-speed dual-clutch tranny, has shown us what to expect from the upcoming S/B model, we don't have the complete tech puzzle for the new M3.
Of course, the 2019 BMW X3 M and X4 M have brought us the new twin-turbo 3.0-liter straight-six with up to 510 horsepower. And the unit will be present on the 2020 M3, once again being offered with multiple outputs.
Then again, we'll have to wait and see if goodies such as an all-paw system with a RWD mode (think: F90 M5) is on the menu. And we can say the same about the number of pedals – here's to hoping the Bavarian carmaker will offer an optional manual tranny.