4.56 gears would be a good investment and would give you the biggest bang for the buck w/ 31s.
A bored out throttle body can help, maybe the larger AFM, too.
Also, at 80+, aerodynamics can help big time, a wind deflector in the rear and maybe one on the hood and if you have the front lifted w/ torsion bars, consider dropping it down an inch or two.

r.c.brown@ieee.org
TruckEditor@tlca.org
Project: 4Crawler
4Crawler OffRoad - 4x4Wire discount code