/Lurch puts his pedantic hat on
RB20det/RB25de/S13/S14/R31 and VL RB30e are all 71C series gearbox's.
VL Turbo is the MX7 which is the early development of the R33 RB25det gearbox.
The only main difference is that the MX7 doesn't have the double scynro's like the R33 box.