Its not the car.... its the age of the car and the insulation you put in the trunk and doors. Get some dynomat and line the trunk. before you line the trunk, put the dynomat in even the smallest crack. this will help keep the sound in the car and stop the "rattle" also you want to make sure you have your license plate tight, top and bottom holes used to hold it on. if you have a license plate frame, take it off. when you have all that done, tern on the stareo loud, close all the doors, and walk around the outside of the car and fallow the sound of the "rattle." what ever it is can be tightened up.
All cars are Pretty much Rattle free. when they get old the parts start to lossen up and start to rattle. Its not hard to fix but eventually all cars do it.