I think the ECU upgrade you are talking about is actually a displacement change to 5.7L. I would bet the Dinan offeres the same displacement "upgrade" to the m3 as they offered to the m6 and m5. It seems that dinan created this mod because it would be applicable to the s65 engine as well.
I would expect the same sort of upgrades for the m3 as they have for the m6 and m5.
I am still waiting for someone to develop a small turbine engine that can be installed in the trunk!