General rule of thumb for removal of rotating mass is for every 10kg of rotating mass you take out has the equivalent effect of taking 100kg out of the car.
If the RB25DET box weighs an extra 20kgs than the weight benefit will be more as for every kilo of rotating mass has the equivelant of 10kilos in the car.
Carlos
If its leaking into the car it will be the master cylinder not the slave cylinder. Its usually better to replace than to rebuild as the cylinder is usaully damaged when they are leaking.
Carlos
RB26Zcar, HR31 GTS/GTS-X's have clutch pack long nose R200 LSD's, manuals 4.11:1, autos 4.43:1. The Z31 300ZX's had long nose R200's as well with ratios of ~3.5:1, 3.7:1 & 3.9:1. Cubes, didn't some of the Infinities have a R230?