Data-logging AFR measurement with narrowband vs wideband questions

1) Can data-loggers (such as the MSD Dashhawk or SCT Livewire) measure AFR accurately, both in open-loop and closed-loop on narrow-band O2 sensors?
No, narro bands are just that, accurate on a vary narrow band of resolution. Near 14.7, too far form that and it just becomes a refrence for the computer to do something, or go into limp home mode.

I’ve read while in closed-loop, the AFR is almost always at or close to stoichiometric (14.7:1). However, in open-loop, narrow-band sensors cannot return an accurate AFR.. true?

Pretty much, depending on what your computer is tuned on for power enrichment mode

2) Is it necessary to install a wide-band sensor to get accurate AFR readings (both in open and closed-loop modes) ? Yes, its the only way

3) Anyone with a MSD Dashhawk or SCT Livewire successfully pulling accurate AFR on the OEM narrow-band O2 sensors? Not possible

Thanks for the quick replies. So, can the OEM narrow-band O2 sensor just be swapped out for a wide-band sensor... or (which is probably the case) do you have to weld in a separate bung for the new wideband O2 ? Just curious if the ECM can use wideband readings to more accurately adjust the fuel map.