Standard gearbox magnesium case made by FF Developments with a dog gear kit also by FF Developments, then Xtrac did a gear kit for rallying and rallycross, for motorsport rear diff housing and front diff housing (part of transaxle) were re-cast in aluminium, Quaife have dome straight cut and helical gearboxes, both use the transfer diff and housing from the original transmission along the with the front differential.
Best part of £40k for the complete transmission drive train

Steve