Our 4in Ultimate System provides less lift than our 6in RTS system but still allows use of 33in or 35in tall tires with cutting for street and offroad use. We have developed this system utilizing replacement upper control arms constructed of 1.50in OD .120in thick wall DOM tubing that attaches to heavy duty Fabtech ductile iron steering knuckles. The factory torsion bars remain in the stock position and use new forged adjusting keys to provide the proper amount of lift.