The EBC Green-Stuffs you got are very nice pads. However, they're geared more towards performance than aesthetics, so they'll put out more dust. EBC also has a Red-Stuff pad that is ceramic, and will produce less dust. However, with less dust, you'll also get lesser braking performance.
Average co-efficients of friction:
GreenStuff = 5.5
RedStuff = 5.0
I highly recommend that you read
this article.