Mini Cooper Dimensions Best Wheel Size For A Mini Cooper S 09?

Best wheel size for a mini cooper S 09? - mini cooper dimensions

Receipt for the delivery of my Cooper 09 s in November. I wanted a population of 16-inch wheels and tires black accessories for them. My friend told me to do up to 17 "because it is more suited to the weight and dimensions of the car. I can not 18" because many potholes on the roads in the region. I go to the market in the 16's 17's should be? Please explain why. Thank you =)