wow 5.29's w/ 31's? 4.56 gears would put you back to stock and make your speedo right. they can be found in just about any automatic 90-95 4Runner for next to nothing. just make sure you check the gear code, there could be 4.88's depending on whether or not the truck had the factory 31" tire option.

but really, are you just getting gears b/c you're installing an a/c system? my truck ran great w/ the factory 4.10's and 31" tires. the speedometer was off by 10 % but i liked the lower revs on the highway for daily driving.

regearing back to stock is never a bad idea, but if i were you i would see how my truck runs once i put the a/c in and then decide if it's necessary.