Tires: Going up Tire Size, michelin hydroedge, dry traction

Question
Hi, I have 4 Michelin P195/55R15 84V (XGT V4) tires replaced with 4 Michelin HydroEdge P195/60R15 87T.
I noticed that the speed rating changes, and what other kinds of effect will I experience when my tires' diameters go up?

People say that V rated tire has better performance and provides better grip and brake.
However, I compare the XGT V4 Tire to my HydroEdge Tire on Michelin Website, HydroEdge scores 10 in both wet/dry traction and 10 in handling while the V4 performace tire only scores 7. Why is that?

Thanks

Answer
Aaron going to a 60 sidewall is not enough to worry about. The only way you will see or feel the differance in tires. Maybe if you are going 75 or 80 MPH around a curve. Car makers have to supply a tire based on how fast a car can go. So if the car can run over 130 MPH the tire must be able to hold up are they can be held responsible.