Having installed a DMD on my SVT, I have a couple of observations to make. First is that the engine is definitely smoother, especially when screaming the revs upwards of 7000rpm. Secondly, there is loss in bottom end tip in. The revs don't come up nearly as quick, due to the extra weight of the DMD pulley. Big difference especially going from a UD pulley to the DMD.
I'm not criticizing the DMD, otherwise, I wouldn't have one on the SVT, but just wanted to let everyone be aware, don't expect any HP gains

but expect a smoother running engine.