Insideline has made mistakes before (stated no 1M was coming) so do not read all of this as if it is set in stone. However, the car is supposed to get a V6. Why? Well, a V6 can sit further back than an I6 and secondly because it will mirror the setup of the N63 V8. That means two turbos sitting in the valley. Knowing BMW, it may just be the N63 platform with two cylinders sliced off. Early guess is the displacement is 3.3 liters. I say just give us the N63 instead in the M3 but ok, fine, the V6 reasons do make sense.
Insideline states the horsepower will be at 429. Then the odd comment is made that this is enough to fend off the C63 AMG. Um, no it isn't. The P31 C63 AMG will eat this alive and we highly doubt Mercedes will just leave the C63 the way it is when the new M3 hits. Mercedes already started the precedent of putting their main AMG V8 in the C-Class so if Mercedes repeats this and gives the C the M157... it's game over kids. The DCT was enough to hold the C63 off and make it close enough but if a twin turbo 5.5 liter V8 comes to town that only needs some software, well, as stated earlier.
The new M3 and M4 are expected to get down into the 34XX range. Which is fine, as this is E46 M3 weight. We like everything for the most part but 429 horses just does not seem to be enough. This would be a very small increase and not proportional to the one which the M5 received. Why not keep the M3 within 100 horses as has been the case with the E36, E46, and E92? Hopefully BMW ups the ante more than this.