The MX32 would originaly have had a W40 or W50 if manual I think (or the historic box that was older than that). So I think any W series box would be the go, but it would have to have a M series bellhousing. I will take a guess and say all M series motors have the same bellhousing bolt pattern, but this may not be correct.
MZ10 Soarer has a W55 alloy box.
Gearbox from a MA61 Supra is your best bet.