Im using greenstuff too,in my turbo,and have found no problems!
I can brake from cold,quite hard,and they is little dust from them too!
But its not only the pads,im also using ebc grooved discs,goodridge lines(all round),and dot 5 fluid.On the rears,i have genuine new rover shoes,and cylinders.(so good,the paint is now bubbling off the rear drums!!

)
So the damn thing stops good,for me,anyway!!