"M3 still KING",
even a BMW-hater has to agree with that. Yet it does not mean that M3 is better than RS5. M3, RS5 (RS4), C63 AMG and IS-F (even if they have for doors), are "practical daily drivable performance cars". So in some way performance is a creteria, and by this creteria M3 wins. If the M3 deserves so much praise, it is not because it is so good by itself, it is thanks to its rivals that gave everything to beat it, but failed. Neither RS5 (RS4), C 63 AMG nor IS-F should ashamed to have failed.
But to say the truth, neither of them failed, because every of these cars is diferent, what is a good thing, as customers also are diferent. Why the M3 has won, everybody knows and we do not need to repete it. And please, no need to go off-topic by saying "but RS5 look better", "RS5 can drive on snow" or "R8 handles like no other BMW can". Here it is spoken about performance, and here the M3 wins. Whether the M3 is better than RS5 is another question, which IMO is 100% subjective as both cars, M3 and RS5, or even C 63 AMG are very good cars, I would say they are equal, with a very light superiority of M3, not because it is better, but because of all the history there is behind it, like it would be with 911 Turbo vs. R8 V10, but this is only psychological superiority. The same could be said in the US about the RS5 about its exclusivity, as they are rare.
We can really thank Audi and Mercedes for making BMW build better and better cars.
IMO, it would have been better for Audi to put the 4.0 TFSI, to have more torque, and so really beat the M3. I admire Audi's courage in trying the beat the M3 on its own battlefield, but I hope it will not go further in such a way, and that Audi will build their own and not some BMW with Audi badge.