License plate is a big one, its loud as hell, try and secure it with all 4 screws if possible, your spoiler, im not so sure on an accord, i stuff felt underneath mine to stop it, but it still rattles with hard hits..
another thing is the underbody, ive seen this on some preludes, the actual under carriage itself rattles and i have no fuggin clue what you would do to fix that and im glad mine doesnt
maybe check the moldings on the side of your car, mine rattled when i first got my system but seem to have stopped on their own
