Picked up my new M3W today, and by the sound of it I am getting the same banging noise on hard acceleration (plus the sort of Bevel Box whine that I thought MMC had eliminated a while ago). I will have to look at the cost of securing the Box to the chassis as suggested above.
Otherwise, it's fantastic.
Banging could be belt tension. MMC have not eliminated BB whine, its luck if you get a quiet one. I doubt if rigid mounting will cure noise. My 2013 had the BB direct chassis mount & when the chassis broke it "gained" the NVH flexible mount. This only had the effect of altering the speed at which the whine was most noticable. The NVH kit is as much use as an anchor & probably weighs the same.
Tim
