yup that's correct. but with the torsen lsd (which is what in the supra rear end), if a wheel is completely off gnd (no traction), that wheel will just keep on spinning and the other wheel won't move. so if you have a supra lsd in your hand and you just turn the main drive shaft, i would suppose the two half shaft moves in opposite direction too (coz' both of them don't have any traction, just like one wheel off the gnd)?

 

hehehe, dunno, i was just wondering. probably even with 20s, the 4.2 rear ratio is still too high. after talking to couple of people (without 20s), while 3.76 gearing is good, it's still a bit high in a sense that you still spin the wheels pretty easy. maybe 20s is a good compliment to the 3.76. 4.2 is VERY high compared to the 3.76, so i think it's too much for the gs with 20s still

btw, just for the record, i believe the e46 m3 has a rear end of 4.2 or so. damn does that thing rev fast

 

You are correct. It depends on the type of LSD whether the wheels (or axle shafts) turn the same direction when the input shaft is turned. With the Torsen (as with an open diff), they will turn in opposite directions when turning the input shaft (pinion) with no traction to either axle shaft.
Just to be sure of this, I tried it with my diff while it was sitting on the floor before the install and yes, the two axle half shaft mounting flanges turned in opposite directions.
I know what aliga is talking about, but with the Torsen it's different so don't let that mislead you...[

 

yeah, torsen is hard to dintinguish @_@