What's the difference between S14 and S15 SR Turbos?

[mrmephistopheles]

Apparently the IDEAL S15 turbo to have is the early version with this part number:
14411-91F00


This isn't really making sense.
according to that first quote.. The late S15/early S15 automatic turbine is the same as the zenki S14 turbine, which isn't possible as those didn't have exhaust outlet divider walls. Also according to that second quote, the 'S15' turbino I have should be a brushbearing while the 'S14' turbo I have should be ball bearing. For sure the S14 turbine shaft spins better but i figured it was just in better shape...