Final drive calculation.

[Bean]

4.3 to 3.3 is a huge step - ask oldeskewltoy I'm sure he can help out.

EDIT: are you sure you currently have a 4.3? as 100km/h @ 4000rpm in 6th sounds more like a 4.77

did run the numbers through a calculator and with a 4.3 you should see about 120km/h - with a 3.9 100km/h would then be just over 3000

according to the same calculator a 4.3 would result in top speed of about 250 @ 8500rpm which sounds about right and should still retain enough torque... personaly I wouldn't go below 3.9.

for highway comfort you might be able to replace the 6th gear with one from an S15 (not sure it fits) - this would give you a considerable taller gear (they are 0.7something)