What have you currently got in it? Im assuming a 4AC.
just out of interest are you actually importing the motor from japan and if so vaguely how much is it all setting you back?
A possible alternative to importing the motor is to have a look at a smallport 100KW from a AE93 rolla or even a bigport 86KW from an ae82 rolla. You should really look into these cos i would think that importing the motor is going to cost you heaps!!
Also not sure if you really need to import a gearbox? I'm sure some of the other guys will be able to tell you definitely but the current T50 should be fine. I mean even if you have to import a bellhousing or make a custom one surely that will be cheaper than getting a whole box in!!
The diff is definitely a good buy though!! You really can't go wrong with that Just be aware though that you may need to make a custom tailshaft!
hope that helps
Cerby