I run 63in burb springs out back with RB's kit. I used the springs to move my axle back (3- 3.5 inches) and out of the way of the gas tank. I have zero interference with full cycling of the suspension. I run rancho 44044's up front which are 2.5 in lift spirngs, for the rear I run the burb springs with the overload removed. It sits perfect. So if you take out the overload you have a 2.5 inch lift spring and if you leave the overload in you would have about a 4in lift spring. This setup flexes like crazy.