as the thread says I put Eagle GTs on my Prius and the handling, road holding and steering have tremendously improved. The tires are all season and either H or V rated but just an excellent performance tire. It really has made driving the Prius fun again. My other car is a G37 but I still enjoy driving the Prius. I do not see any degradation in mpg. I can still get the 50 or 51 calculated if I drive in ECO mode but nowadays I tend to drive in PWR mode all the time.
That's kind of cool. I was wondering what happened if I got 17s (the standard Prius ones) and put "sticky" tires on it. I say "sticky" in quotes because no street tire will match the performance of the Michelin Pilot Super Sports I have on my BMW =D