first, only the R34's came with the 6speed.. the others were the same as the gts-4 or gts-t but with a transfercase..
second, besides that of the Nismo SR transmission I dont think any come with the correct bolt pattern. The guys here are looking into modifying the 350Z bellhousings with that of the Nisssan 10bolt.. I may be getting ahold of one of these and taking the engine side, with the tranny side to a machine shop I know, with measurements and have the belhousing remade custom..