I have an Ergodyne bass too, mine's a 5-string. It appears they use either made-in-Korea 'Bartolini' pickups or Ibanez' knock-offs that are the same size. US Bartolini MK series pickups should be a "drop in" replacement (meaning their the same size as the OEM pickups, no routing of the bass should be needed). The ability to solder is needed for installing pickups and preamps, and you really need a multimeter (volt-ohm meter) to troubleshoot if things go wrong.
I'm planning on upgrading my Ergodyne by replacing the neck pickup with a US made Bart and replacing the "Phat II EQ" gizmo with a differerent preamp, probably an EMG.
"I have no actual information, just what the salesman told me."