Alfa 6 speed boxes, to fit fiat 2.0 20V ?

[jayfish]

Just at the start of a little project and am wondering if anyone has any knowledge/experience with fitting alfa boxes to the 5cyl 20v fiat engine. If specifically after an Alfa box for two reasons, better internals and greater availability/lower cost.
Not after much info yet as this idea is still in the embryo stage, but needs careful planning.