the only M32 which will fit is from the z22yh engine, you can also use the F40 gearbox from the z20net vectra C turbo.
The easiest way to do the conversion on a vectra C is to find a complete 6 speed set up on a vectra C at the breakers - gearbox, gear cables, gear stick assembly, driveshafts, clutch, flywheel and gearbox mounts.
Nut and bolt job, so quite straight forward (y)