Need some more highway oomphh

Yeah, I just put some cheapie 31's mounted on some wrangler 15x6 rims on my 1994 DD cherokee with the 4.0. I have no lift and stock 3.55 gears with an automatic. What I don't get is how it pulls strong up to about 30 no matter the load (4 people fulltank) and sucks on the highway. These tires are inward of the flares and I know every gear is overdriven now, but acceleration feels better than crappy 235/75 wrangler radials and I figured acceleration would be hurt most. All I've done for mods is a homebrew Trailblazer FIPK(not K-N), firepower ign, dynomax catback, spacer, NGK plugs and racked up 126 k miles. Just confused .

Regear the axles with 4.10 gears to restore performance lost due to the bigger tires. If you plan to go to even bigger tires like 33's, go for 4.56 gears.
Regearing will be far more effective than bolting on a whole raft of performance mods.