ok my friend has a gsr that just came in, gears in the tranny are fine, but the housing got kinda messed up (sounds weird but ill try n geta pic) but i can i drop the gearing into my ls tranny and put in the lsd????

 

The cases are the same (any b-series internals 92+ fit any case 92+). Check all clearances as per the Helm's and you should be set.