I'm putting on DP very soon. Most of the big name manufacturers have pipes for the M1000. The product listing on some company web sites are not up to date. You should call the company directly just to be sure.
header diameter and mount points are the same on the m1000 as on the other monster models except for the new s4r. the difference in the stock mufflers is that the 1000's muffler bodies are slightly larger so there's more cubic volume for gas resonance/expansion. this helps account for the restrictive quality of the muffler's design and is not really a factor when dealing with aftermarket cans since they're essentially straightpipes.