Yes you can change the tyres to 16inchers but we wont recommend that as it would lower the fuel efficiency and the top speed of the car and the driving dynamics would also get changed.
Hey, it is great that you wish to buy a new car and we are happy to be a part of your new car purchase. It is hard to pick one out of the cars that you have selected. If you wish to go for the best automatic transmission, you should choose, Volkswagen Vento, it comes equipped with a DSG which is the best among all the options. Volkswagen is high on maintenance though. If you wish to go for a car which is decently powered and also offers good amount of features and is easy to maintain. Go for Honda City. Click here to check out the comparison.
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.