I think FATS on this forum has an RB26 in his R31, with a Ford XR6T turbo hanging off the side.
He is using the stock RB20det gearbox for now.
he is also using a stock GTR clutch.
now, from what I have heard, and video's I've seen, FATS doesn't baby his car... he has about 280rwkw I believe, and I'm sure that the midrange torque from that motor/turbo combo is fairly hefty.
So there is plenty of life in the RB20 gearbox.
sure an RB25 one would be a better option, but when I do this conversion, I will not be spending an extra $2K to replace a gearbox which is working fine.
I plan to do my engine conversion for $5K - so obviously it will be a simple, budget build.
*yells at calendar.. "hurry up 2006"*