This is not a very "scientific" as I don't know how stiff your rear springs are. But perhaps it will you help out by bringing this post back to the top and other members with more experience and knowledge will see it.
Place enough weight in the car to approximate what you may be carrying in it (passengers, dog, tolls, etc.). Then bounce on the back bumper.
I told you it was very "scientific".
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote