I don't think I have ever owned a car that didn't have a rattle/squeak/tap from the plastic trim. My Jazz (my first Honda) is no different. The passenger side cup holder has a rattle at certain speeds or terrain, and just a quick squeeze of the recess generally stops it. I also get a buzz that seems to come from up near the driver sun shield... but maybe from the rear seatbelt area too. At one time we used to hear a creak from the driver side when on B roads going up and down hills and around bends. Not every journey, and fortunately it seems to have stopped. I have just hit the 10k mark, and these rattles/buzzes are very minimal, and nothing worse has happened. I just think its the nature of plastic on plastic, flexing and reacting to noise/vibration/pitch.