First Gear: 4.313:1
Second Gear: 2.330:1
Third Gear: 1.436:1
Fourth Gear: 1.00:1
Fifth Gear: 0.838:1

that info is from here: http://en.wikipedia.org/wiki/Toyota_R_transmission so it may not be 100% for sure... but.... if it is correct, it wont do anything for the 5th gear.....

have you thought about changing the axle gearing? thats the only thing i can think of other than adding a klune type undersrive system like they have for samurais.. but i dont know if anyone has that for a toyota