[dBlast]

First of all if you are changing tire and wheel sizing the overall diameter (rolling circumference) or total height should remain the same for proper speedometer reading and gearing. If you are going from a 15 inch wheel to a 16 inch wheel, you will have to go to a lower profile tire to match the stock diameter.

It depends what you want. Lower profile tires will give you better cornering performance. Taller profile tires will give you more comfort. If all you want is to go fast in a straight line then a smaller wheel will give you more speed since wheels weigh more than tires.

Below are some links to help you with tire sizing:


link to focus friendly tire size chart

good tire size calculator