I need to replace the original 185/65R15 Integrity tires, but there are many questions. 1) What is the effect of going to the 195/60R15 tire? It seems to have the same rev/mile, so what is the difference? 2) Which tire has a bigger contact patch with the road, a x/65R15 or a x/60R15 tire? Is the difference insignificant in real world performance? 3) The 2010 Prius now has 195/65R15 tires. Will that size tire give a very slight improvement in mpg over the 185/65R15 tires (same manufacturer/tire line)? Does anybody know why Toyota switched sizes? 4) Has anybody used the new Continental ProContact with EcoPlus Technology? 5) Does anybody choose a tire based on the country of manufacture? Would you choose a different size just to get one made in the U.S.? 6) Of the three sizes, 185/65R15, 195/60R15, or 195/65R15, is there any overriding reason to choose one size over the other?