what adapter plate are you talking about? cause if you are talking about the 3" inlet adapter on the compressor housing, then i don't see how that is relevent

 

look on the turbine inlet, you see the nice adapter plate? If not the two differnt colors should be a clue. Also, how else do you think they can fit a .64 gt28r with a t25 flange onto a stock manifold????

Its what ATP use to due in the old stage 2 kits and greddy is doing now for the 1.8t's. There are tons of threads talking about the adapter plate leaking cause of the heat and tightening of the bolts warping it. If you install one of these, you better never plan on taking it off because the more you do the great the chance of warping accures