On your 3.7 what have you set the torque at? My mech says that on the NISMOs most people set up to tight and depending on condition of clutches going less is better they wont lock up to soon, also if the oil is to heavy will also tend to lock up till up to temp but have to be carful not to cook unit if using to lite oil/add mix Thats why may racers end up using a cooler for the diff.
Talk to Greg Ira he runs the power bruits and NISMOS on his car and may be able to give you some imput on torques.
Another source is the 510 comunity lots of them have converted to the 180s from the 160s and may have some of the 110 gears sets
A good sourse for the NISMO set up is Gordon Glasgow (English nissan guru) www.gordon-glasglow.org/lsdtech.html
Another info source is http://kmhafer.datsun510.com/Subaru.htm
You may already have all this if so disreguard