In terms of the jz and uz, there would not be destruction of torque by the auto gear. Have tried and tested the auto 2jz-ge (vvti) and the 1uz swapped into the 75 mark 2 and land cruiser 2, respectively. Didnt for a second did i have to think that i need more torque
If you can find the jz with the proper manual gearbox, its the sweetest thing.