Except that a tranny cooler can also reduce engine temps, and the biggest cause of failure in TC'* and fluid is heat. Heat breaks down the fluid, then you pay $80 for a flush. I'd rather do buy a $40 cooler, and flush every two years, rather than flush once a year.
I also have a trans temp gauge. Climbing the mountain passes around here in the summer with tranny temps of 240°+? No thanks.
I would guess that if your in a mountainous region then it may make sense to have one in. However in the ohio area (flat) I have never seen my tranny temps above 180-190 even after long hard driving.
So if i put the pulley off a 1992/93 supercharger witch is a 2.5 am i going to have to put a larger idler pulley on to take up some slack? If so what size of pulley am i going to have to put on? Or will i be fine?
2.5 is the typical performance diameter for a 94/95. Keep the stock length of belt, and get the ZZP oversized idler pulley. Otherwise you won't have enough belt wrap around the smaller SC pulley, and it may slip under hard accelleration. There are pics on my website that will show you the size difference.