muffler position

hey i was wondering what position is correct for the muffler to be? i actually have a rear add on kit and so how close to that is right? should it be touching have just a tad but space inbetween? the oem hangers either holds it tight onto the add on or spaces it too far so whats right?..thanks

Normal should be around 1 to 1 1/2 inches from the bumper or lip etc.