Trying to figure out if I will need to regear my rear end

[D-n-Tyke]

I am trying to figure out (and then possibly budget) if I will need to regear my rear end. Going to be running a 6.0/4L80E. Current gears in the rear end are 3.08. Anyone running this set up and having it work well for them. I would like to get half way good gas mileage, well as best as I can thru gearing, not running high RPM on the freeway, but also don't want it to be a slug off the line. What do you guys suggest, run what I have, or regear it?

4L80E Ratios
1st 2.482
2nd 1.482
3rd 1.000
4th 0.750

R&P 3.08