Hopefully I won't get too much heat from this but I just want to clear up some terminology since different people use different terms when talking about higher or lower gear ratios.
The "gear ratio" we are talking about is determined by the number of teeth on the ring and pinion gears in the diffs. We divide the number of teeth on the ring gear by the number of teeth on the pinion. So if the ring gear has 40 teeth and the pinion gear has 10 teeth the gear ratio is 4.00. That also means for every full turn of the pinion, the ring turns 4 times. The more times the pinion has to turn to produce a full turn of the ring, the lower the gear ratio. So, for example, 5.13 is lower than 4.10. This is sort of confusing because the bigger the number, the lower the ratio. Generally when mechanics or auto people say they want lower gears, they mean they want something like 5.13 gears instead of the factory ratio of 4.10. The 5.13 ratio is lower than 4.10 but the number 5.13 is higher than 4.10.
This is potentially confusing at least to me since I don't always know what the person is saying when they say lower or higher - do they mean lower/higher ratio or lower/higher number?
Defcon's post is an example where he says, "A little lower would get better mileage, a little higher would get more power." I assume he is saying in his example that the 4.22 gears will get better mileage (which is correct) than 4.63 gears because 4.22 is a higher ratio even though the number 4.22 is lower than 4.63.
For whatever its worth I think we should mean gear ratio, not the actual number, when using the terms higher or lower gears. So lower gears means 5.13 as compared to say 4.10.