Have you installed your own kit exhaust?

Yes, over the axle clearance. When you lift your car up via floor jack, bumper jack...what happens? The car goes up first and the tires, axle stay on the ground. This increases the clearance between the body and axle/tire and the spring bends which is also a clearance changing item to consider.

If you were to jack the car up and support it in the rear by jack stands placed under the axle tubes that would work too, right? The weight of the car would be on the springs....