Adj. arms allow you to set axle position and the pinion angle properly. When you lift a jeep all the suspension is effected and the axle has to be set to match the new setup. If you are using fixed arms you could easily be adding a problem to a good lift. The lower arms position the location of the axle and the upper arms set the pinion angle.
4" Teraflex long arm lift. D30 tubed with chromoly axles, high pinion, powertrax no-slip and Warn Lockout Hubs. D35 w/ultimate 35 upgrade OX locker, 4.56 gears. NP231HD, Air on Board, Warn M8000 Winch.