The T50 in my SA60 has 300k kms on it and is a little tired. I'm tossing up options for replacement.
As I see it:
T50
-Cheapest and easiest would be another T50, bolt straight in for $200 odd
-It's an old box and wouldn't be particularly helpful with any potential future 3SGE swaps
W5*
-Bellhousings to bolt to S series do exist, the starter is on the correct side (I think) and is much stronger than the T50
-Cost around $400 for the box alone and would require adjustment of the drive shaft and quite likely the shifter position
J160 (altezza 6spd)
-Comes with S series bell, is 6 speed, can be had for $400-500
-Most difficult to install? I know the shifter position is quite far back, I've been told that the starter is on the intake side (can anyone confirm?) and I suspect may not not reach the 1S flywheel. What else?