The company claims a mileage of 16.8 kmpl for the manual transmission models and 15.6 kmpl for the automatic transmission models. Experts believe that it offers mileage around 14kmpl in city roads while on highway it gives 17kmpl which makes it the quite fuel efficient car in its segment. You can please follow the link below for further details:http://www.cardekho.com/carmodels/Honda/Honda_City#Honda_City_Mileage
Certainly, you can get your car modified as per your choice. Coming to the front grill, you can replace it with the different grill. For that, we suggest you to get in touch with the authorized service centre as they will be the best people to suggest you few compatible grills to choose from.
Click here to find the Honda service stations by selceting your city in the drop down list.