These renders , according to what i've read and seen so far, should be accurate at 95% at least, probabilly even more. This renders have been posted on BIMMERPOST | BMW Forum, BMW News and BMW Blog. The auctor did with Photoshop a mix among the future 4 serie and retouched parts of some current M. Credits to the auctor must be given since he did a great job imo. I personally think the interiors aren't as accurate as the carbody, for example the gear stick will be surely different (it lacks the M badge and it's identical to a base model). The steering wheel also will be different imo, since this is the same as the Sport Line versions sold actually in Italy for the new 3 serie apart from the seams and the thickness. Anyway, it seems a BMW insider told this carbody is very very closed to the concept which will be officially revealed at the end of 2013. The production M4 should be in the showrooms in the middle of 2014. My personal thought is that the engine power will be increased on the final model since no M has been less powerful that the previous one so far. I've also attached a pic of the specs of the model as it appears here. Straight six engine, displacement 3.000 cc, twin turbo, 415 hp, carbody with 40 kg less than the current M3 coupe'.