I would find a level surface, and some good reference points on the car body, and see if the car is tilted or the flares are one the car incorrectly. Or if something else is going on.
Reference points might be something obvious like the back bumper, or the bumper mounting points. Or the inner wheel well arches. Or the sub-frame mounting points for the suspension.
If the car boy is tilted,then adjusting the suspension is reasonable,and will bring the body back in to line. If the flares are off, then adjusting the car body will introduce other weirdness, like a tilted look from the back.