Open centres are a different kettle of fish, but who cares about them?
Biased99 probably cares . I mentioned the open centres as only the 91/92 Grandes had LSD as standard and as such Biased99's car is probably open centre, otherwise he wouldn't be considering a swap unless it was for the higher ratio available in the MA70.
I'm pretty sure my 89 MX83 was a G312 but that was 8 years ago and is sorta foggy now.