Question about T5's
 

I recently tore down the Tremec T5 outta my 2000 6 cyl, and found out that its gonna need a new input shaft and counter bearings. A friend of mine knows where I can get a lower mileage working T5 (also Tremec) for a good price, but it came outta a GT. I'm wondering if because of the difference in transmission gear ratios between a GT and my 6 cyl that the two aren't interchangable. I'd imagine that the GT's T5 is geared down a bit to handle the extra torque load, but am not sure. Anyone dealt with this before?