I want to modify my car

You can do n number of modifications to your car depending on how much money do you have. Sunil and Nigel are good. Contact them and tell them your requirements.Modifying a 2000 model Honda City to realistically look like the SLS AMG is beyond the ken of any Indian car modifier and you would end up with a caricature. Don't do it. It will cost a lot of money and you will not be satisfied with the end result, unless of course if you are stupid, in which case you can surely go ahead with such a modification.