the DSM green is an open volute, 7 or 8cm^2 housing, the Evo Green is a divided 10.5cm^2 housing thats the difference.
look at the picture i posted of the Original FP Green(before there was a DSM or Evo Green) even the compressor housings are different. FP has made huge changes to its appearance.
the original Evo Green used a stock 05 Evo 8 housing(turbine/compressor) that was machined to fit the Greens new wheels, where now they offer them with 82mm anti surge housings.