depends on the spring you're using... stock... non-stock? actually, the rear should be about 3/4-7/8 inch higher than the front of the car... measured at rocker panel just behind front wheel and just in front of rear wheel. with dinan spring kit, i used the 4th slot from top... then moved it up to 3rd from top. once on the car.. .it's easier to try to push the c-clamp thing up a notch than down... so perhaps set it on the lower side... and if not the right height... you can try to push it up... to a point...maybe 3rd from top... and higher might require a spring compressor.