I replaced the pickups of my Tobias 6-string with 2 EMG 45J pickups, and I'm VERY happy with the result. Better B-string (I've always felt that the Tobias Bartolini's should have had a flatter top; the outer strings were too far from the pickups), more of a warm, yet bright, J-bass sound. Works well together with the Batolini preamp.
See the Youtube video for a demo: http://www.youtube.com/watch?v=PBgF1...kB5XEOFhhrbL4Q
I also had a great chance of testing it this weekend: Musical star Linda Wagenmakers sang at our church. See http://mediaspeler.bethel.nl/2013/02...a-wagenmakers/
(music starts around 8:00)