Interesting point. True that unsprung weight is very important. Adding 3-4 pounds of extra tire weight per wheel total 12 pounds at a supposedly 3.47 to 1 ratio amounts to adding around 41 pounds of sprung weight. But....another way to look at it is the additional tire contact with the road may increase your ability to travel faster through the curves. On the other hand... lighter wheels/ tires generally improve the ride. Although.... if your going to drag race your i8, the extra unsprung weight may add 1/10 second. But....I don’t see many high performance cars with skinny tires. Lots to consider. Ultimately.... fat tires look cooler.