To answer your questions: 1) I have seen at least one pair of SR100 with HP1000 drivers but no red lettering. 2) I have not seen any other Grado models with red lettering other than SR100. HP1000 drivers also show up in some early SR325, as well as SR100/200/300. The HP1000 drivers didn't get into SR series because Grado Labs ran out of never drivers. It happend BEFORE John had any other drivers other than the HP1000 ones.