I just bought a 2006 Mazda3 s 2.3l hatch and it needs new tires. I picked out a well-reviewed 17in set using the make/model/trim at tirerack, but after going and actually looking at the size of the tires on the car, they are 16in. These are the tires that came new on it... is it normal for these cars to come with a smaller size than the default? Is there a benefit to getting 17in wheels?