I disagree, 4.88 is more ideal for 33s on a 3.0L.
The 3.0L is a revver. If it can't spin fast enough, it'll actually suck more gas because of it.
I will say however your mileage likely won't be very much different with 4.56 vs. 4.88, but 4.88 will give you quite a bit more oomph.