Yes, Honda City is my first car and I am loving it. I still stand by the statement that out of the Options available in the C2 Segment Sedans, considering all aspects, Honda City does edge out from the competition. The point is not just about quality when choosing a car. If that was the case, then probably you should have gone with Vento which has a highly superior build quality. But even you chose peace of mind by going with a Honda City despite knowing all the bashing that has been going around on this Thread and other threads.
Well there are people who are really unhappy with the car and went on to sell the car and buy a different car. That's also a part of this thread. Probably you must have read those posts too. Still you chose to buy the Honda City.
Sound Insulation is an individual's perspective. Probably your expectations are much higher which may require further sound-proofing of the car. This is something one can easily make out while taking a test drive and it's not something which becomes known only after buying the vehicle.
I do not wish to throw back at you, but certainly the above derived statement itself shows some lack of knowledge. None of the AC Filters are designed for such a low life of 2500 Kms. Also the AC filters are not Honda make. These are from some other suppliers who must be supplying to other car manufacturer's too.
With regards to the issues faced by you and being discussed on the forums the rattling noise, I mentioned that I am facing it too. Live with it or Sell it are the only options available.
Fuel Economy, I would once again iterate, is again an individual's driving style. There are a lot of people who have indicated similar FE as what I indicated. FE as low as yours is either driving style problem or something in the car. Even if you go to the ASC, they will deny it saying it's your driving style. Hence, my suggestion was to try a more sedate driving style and if the problem persists take it up with the ASC.
Auto-Acceleration - Down-shift to third gear at 50 and take your foot of the accelerator, the car speed will come down to 35 kmph and keep cruising at that. What else is expected? should the car come to a standstill and stall on third gear because there is no accelerator input.