I posted this some time
ago. It is a pretty clear shot of the brakes. It is not entirely clear if they are multi-piston (usually easy to tell but these are darn tricky) but they sure look a lot bigger
than the E46 M3 brakes (calipers and rotors).
I think, if I recall, these look exactly like the M5 brakes if those are single pot IŽd guess we will be getting that system. Since those are rated for a 4000+ lb vehicle going about 195 mph. For the weight and speed of the new M3 it should only need about 70% the braking capacity of the M5 so this system should be quite good.
I know OEM BMW systems can be a bit inconsistent, but after a mild upgrade to my E36 M3 system, I find it adequate for medium speed track work and very hard street/canyon/twisty work. I have the two piece OEM M3 euro floating rotors, stock pads and aftermarket stainless lines. Very tough to over heat or warp this setup. On the other hand I have heard totally mixed stories about the E46 M3 setup.